WebView (EdgeHTML) for Windows 10 apps

Článek
12/02/2020

Note

The features described in this document are no longer being maintained. For more information on the new WebView2 control, see Introduction to Microsoft Edge WebView2 (Preview).

The WebView (EdgeHTML) control enables you to host web content in your Windows 10 app.

You can use it as a XAML element (for Universal Windows Platform (UWP) apps and Windows Forms and WPF desktop applications), or an HTML element (x-ms-webview)/DOM object (MSHTMLWebViewElement) for JavaScript-based Windows 10 apps, as described here.


Events	departingFocus, MSWebViewContainsFullScreenElementChanged, MSWebViewContentLoading, MSWebViewDOMContentLoaded, MSWebViewFrameContentLoading, MSWebViewFrameDOMContentLoaded, MSWebViewFrameNavigationCompleted, MSWebViewFrameNavigationStarting, MSWebViewLongRunningScriptDetected, MSWebViewNavigationCompleted, MSWebViewNavigationStarting, MSWebViewNewWindowRequested, MSWebViewPermissionRequested, MSWebViewProcessExited, MSWebViewWebResourceRequested, MSWebViewScriptNotify, MSWebViewUnsafeContentWarningDisplaying, MSWebViewUnsupportedUriSchemeIdentified, MSWebViewUnviewableContentIdentified
Methods	addWebAllowedObject, buildlocalStreamUri, capturePreviewToBlobAsync, captureSelectedContentToDataPackageAsync, invokeScriptAsync, getDeferredPermissionRequests, getDeferredPermissionRequestById, goBack, goForward, navigate, navigateFocus, navigateTolocalStreamUri, navigateToString, navigateWithHttpRequestMessage, refresh, stop
Properties	canGoBack, canGoForward, containsFullScreenElement, documentTitle, height, process, settings, src, width

Syntax

// Feature detect for webview support
if (MSHTMLWebViewElement) {
    let wv = document.createElement('x-ms-webview'); // Use CSS to set width, height and other styles
    wv.navigate("https://www.example.com");
    document.body.appendChild(wv);
}

Remarks

WebView versus iframe

Like a standard HTML iframe element, you can use WebView to load remote pages over HTTP and local pages (ms-appx-web:///) from your app package. However, the WebView can also:

Load pages and resources from your ApplicationData (local, roaming, temp) folders (ms-appdata:///) and in-memory streams (ms-local-stream:///)
Provide browser-like controls: for going back and forward in navigation history, and stopping or refreshing the current page.
Capture screenshots of web content making it easy to implement the Windows 10 app Share contract.
Allow JavaScript code running within a webview to raise custom events (MSWebViewScriptNotify) to your app, and allow your app to run JavaScript within the webview (invokeScriptAsync).

Provide you with fine-tuned webview content events:

WebView DOM event	Description
MSWebViewNavigationStarting	Indicates the WebView is starting to navigate.
MSWebViewContentLoading	The HTML content is downloaded and is being loaded into the control.
MSWebViewDOMContentLoaded	Indicates that the main DOM elements have finished loading.
MSWebViewNavigationCompleted	Indicates the navigation is complete, and all media elements are rendered.
MSWebViewUnviewableContentIdentified	The WebView found the content was not HTML.
UnsafeContentWarningDisplaying	The WebView shows a warning page for content that was reported as unsafe by Windows SmartScreen Filter.

...including corresponding events for iframe content loaded within a WebView (such as MSWebViewFrameNavigationStarting and so on).

Printing

When a Windows app using JavaScript is printed, the <x-ms-webview> tags are transformed into <iframe> tags before printing. Besides the normal difference between displaying on screen and rendered for print, CSS styles applied to <iframe> elements are then applicable to the <iframe> transformed from <x-ms-webview>.

Service workers

Starting with the Windows 10 October 2018 Update (EdgeHTML 18), service workers are supported in the WebView control (in addition to the Microsoft Edge browser and Windows 10 apps with JavaScript).

x64 app architectures require Neutral (Any CPU) or x64 packages, as service workers are not supported in WoW64 processes. (To conserve disk space, the WoW version of the required DLLs are not natively included in Windows.)

Threading model and reliability

Creating a WebView via document.createElement("x-ms-webview") or via <x-ms-webview> markup creates a WebView on a new unique thread in the app's process. Running on a new unique thread means that long running script from one WebView is unable to hang the app or other WebViews. Creating a WebView via the new MSWebView() constructor creates a WebView in a separate WebView process. Running in a unique process means that in addition to protection from long running script, the app is also protected from web content that crashes the WebView process. Creating a WebView via the MSWebViewProcess.createWebViewAsync method also creates a WebView in a separate process but allows the caller more control over process settings and grouping WebViews in WebView processes. See MSWebViewProcess for more information.

WinRT API access

A UWP app may allow HTML documents inside WebViews to have access to WinRT APIs. This is via the WindowsRuntimeAccess attribute of the Rule child elements of the ApplicationContentUriRules element of the AppxManifest.xml of the UWP app. Set WindowsRuntimeAccess to 'all' and HTML documents with matching URIs will be allowed to use WinRT. This is the same as providing WinRT access to HTML content in JavaScript UWP apps so see Call WinRT APIs from your PWA for more information.

UI related WinRT APIs may not work when called from a WebView running on its own thread but may work when called from a WebView running in a separate WebView process. When using a WebView on its own unique thread, that thread is not the app's view thread. Some UI related WinRT APIs require to be called from the app's view thread. WebViews created in a separate WebView process do run on a view thread and so should not face the same restrictions as WebView's running on their own unique thread. If you have trouble with UI related WinRT APIs in a WebView ensure that you're using a WebView in its own WebView process as described above.

AppCache storage limitations

Applications using JavaScript support of the Application Cache API (or AppCache), as defined in the HTML5 specification, to create offline web applications must observe available storage limitations. This is especially true in devices with limited memory space. The practical limits on the size of the AppCache are always a function of available disk storage space. The general guidelines are shown below.

Volume size	AppCache per domain	AppCache per user
Up to 4GB	10MB	50MB
4GB to 16GB	50MB	500MB
16GB to 32 GB	50MB	1GB

All Windows 10 apps are intended to use the same AppCache quota model, so the available disk storage limitation applies to both desktop and phone apps. The is also a hard limit after pages loaded inside WebView together have consumed 1 GB of AppCache space; requests for additional AppCache storage above this limit will be denied.

For more information, see the HTML WebView control sample and the JSBrowser's Harnessing the WebView control documentation.

Events

departingFocus

Indicates focus departing from the webview into the app. Fires when the webview's top level document calls window.departFocus. The FocusNavigationEvent args in the departingFocus event match the parameters provided to departFocus except the origin parameters are translated from the webview's document's coordinate space to the coordinate space of the webview host document. See the webview.navigateFocus method and corresponding window navigatingFocus event for transferring focus from host to webview. See the TVJS's Direction Navigation library for an example of an implementation of focus navigation via keyboard or gamepad that handles this event.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("departingFocus", handler);
webview.removeEventListener("departingFocus", handler);

Event Information


Interface	FocusNavigationEvent
Synchronous	Yes
Bubbles	Yes
Cancelable	No

MSWebViewContainsFullScreenElementChanged

Occurs when the status changes of whether or not the webview currently contains a full screen element. Use the containsFullScreenElement property to the current value. Full screen element here refers to the Fullscreen DOM APIs notion of a full screen element via the element.requestFullScreen and document.exitFullScreen DOM functions.

function containsFullScreenElementChangedHandler(eventInfo) {
    const applicationView = Windows.UI.ViewManagement.ApplicationView.getForCurrentView();
    if (webview.containsFullScreenElement) {
        webview.classList.add("fullscreen"); // Have the webview fill the app view
        applicationView.tryEnterFullScreenMode(); // Have the app view fill the screen
    }
    else {
        webview.classList.remove("fullscreen"); // Return webview to normal
        applicationView.exitFullScreenMode(); // Return app view to normal
    }
}

// addEventListener syntax
webview.addEventListener("MSWebViewContainsFullScreenElementChanged", containsFullScreenElementChangedHandler);
webview.removeEventListener("MSWebViewContainsFullScreenElementChanged", containsFullScreenElementChangedHandler);

Event Information


Interface	Event
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewContentLoading

Indicates that the HTML content is downloaded and is being loaded into the control.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("MSWebViewContentLoading", handler);
webview.removeEventListener("MSWebViewContentLoading", handler);

Event Information


Interface	NavigationEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewDOMContentLoaded

Indicates that the main DOM elements have finished loading.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("MSWebViewDOMContentLoaded", handler);
webview.removeEventListener("MSWebViewDOMContentLoaded", handler);

Event Information


Interface	NavigationEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewFrameContentLoading

Indicates that the HTML content downloaded and is being loaded into the <iframe> control.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("MSWebViewFrameContentLoading", handler);
webview.removeEventListener("MSWebViewFrameContentLoading", handler);

Event Information


Interface	NavigationEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewFrameDOMContentLoaded

Indicates that the main DOM elements have finished loading in the <iframe>.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("MSWebViewFrameDOMContentLoaded", handler);
webview.removeEventListener("MSWebViewFrameDOMContentLoaded", handler);

Event Information


Interface	NavigationEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewFrameNavigationCompleted

Indicates the navigation is complete, and all media elements are rendered in the <iframe>.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("MSWebViewFrameNavigationCompleted", handler);
webview.removeEventListener("MSWebViewFrameNavigationCompleted", handler);

Event Information


Interface	NavigationCompletedEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewFrameNavigationStarting

Indicates a <iframe> within a webview is starting to navigate. This is fired before obtaining any resources from the network for the navigation. The navigation is not started until all MSWebViewFrameNavigationStarting event handlers complete. This event is cancellable via calling eventArgs.preventDefault(). If cancelled, the WebView will not perform the navigation.

function frameNavigationStartingHandler(navigationEventArgs) {
    // Cancel all navigations that don't meet some criteria.
    if (!navigationEventArgs.uri.startsWith("https://example.com/")) {
        navigationEventArgs.preventDefault();
    }
}
 
// addEventListener syntax
webview.addEventListener("MSWebViewFrameNavigationStarting", frameNavigationStartingHandler);
webview.removeEventListener("MSWebViewFrameNavigationStarting", frameNavigationStartingHandler);

Event Information


Interface	NavigationEvent
Synchronous	Yes
Bubbles	No
Cancelable	Yes

MSWebViewLongRunningScriptDetected

Occurs periodically during uninterrupted script execution in the webview, letting you halt the script.

function handler(eventInfo) {
    const stopPageScriptThreshold = 5 * 1000;
    if (eventInfo.executionTime > stopPageScriptThreshold) {
        eventInfo.stopPageScriptExecution = true; // Stop the long running script if it goes over our threshold
    }
}
 
// addEventListener syntax
webview.addEventListener("MSWebViewLongRunningScriptDetected", handler);
webview.removeEventListener("MSWebViewLongRunningScriptDetected", handler);

Event Information


Interface	LongRunningScriptDetectedEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewNavigationCompleted

Indicates the navigation is complete, and all media elements are rendered or there was a navigation error. Check the event args isSuccess property to tell if the navigation was successful and the webErrorStatus property for details on the navigation error. Navigation errors can occur before obtaining any content from the network for instance if the hostname of a URI does not resolve in which case the MSWebViewNavigationStarted event will fire followed by the MSWebViewNavigationCompleted event. Navigation errors may also occur after receiving an error page from a web server, for instance a 404 page from an HTTP server in which case all navigation events will fire, MSWebViewNavigationStarting, MSWebViewContentLoading, MSWebViewDOMContentLoaded, and then MSWebViewNavigationCompleted. To provide an app navigation error page for cases where the web server hasn't provided an error page, you'll need to check if MSWebViewContentLoading hasn't fired for a failed navigation which indicates there is no server provided error page.

let hasContent = false;
webview.addEventListener("MSWebViewNavigationStarting", () => { hasContent = false; });
webview.addEventListener("MSWebViewContentLoading", () => { hasContent = true; });

webview.addEventListener("MSWebViewNavigationCompleted", navigationCompletedEventArgs => {
    // Navigation failures may or may not come after getting an error page from the web server.
    // We keep track of the ContentLoading event with hasContent to tell if we have an error page from the server.
    // So we only navigate to our app error page when there's no server provided error page.
    if (!navigationCompletedEventArgs.isSuccess && !hasContent) {
        // Pass our failed URI and error details in the query and the error page script can read it as appropriate.
        webview.navigate("ms-appx-web:///appErrorPage.html?" + 
            "uri=" + encodeURIComponent(navigationCompletedEventArgs.uri) + "&" +
            "webErrorStatus=" + encodeURIComponent(navigationCompletedEventArgs.webErrorStatus));
    }
});
 
// addEventListener syntax
webview.addEventListener("MSWebViewNavigationCompleted", handler);
webview.removeEventListener("MSWebViewNavigationCompleted", handler);

Event Information


Interface	NavigationCompletedEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewNavigationStarting

Indicates the webview is starting to navigate. This is fired before obtaining any resources from the network for the navigation. The navigation is not started until all MSWebViewNavigationStarting event handlers complete. This event is cancellable via calling eventArgs.preventDefault(). If cancelled, the WebView will not perform the navigation.

function navigationStartingHandler(navigationEventArgs) {
    // Cancel all navigations that don't meet some criteria.
    if (!navigationEventArgs.uri.startsWith("https://example.com/")) {
        navigationEventArgs.preventDefault();
    }
}
 
// addEventListener syntax
webview.addEventListener("MSWebViewNavigationStarting", navigationStartingHandler);
webview.removeEventListener("MSWebViewNavigationStarting", navigationStartingHandler);

Event Information


Interface	NavigationEvent
Synchronous	No
Bubbles	Yes
Cancelable	Yes

MSWebViewNewWindowRequested

Raised when content in webview is trying to open a new window. If the event isn't cancelled the webview will launch the URI of the new window request in the user's default browser.

function handler(eventInfo) {
    // Prevent the webview from opening URIs in the default browser.
    eventInfo.preventDefault();
    
    // Only allow https://example.com/ to open new windows.
    if (eventInfo.referer === "https://example.com/") {
        // Perform some custom handling of the URI.
        openUri(eventInfo.uri);
    }
}
 
// addEventListener syntax
webview.addEventListener("MSWebViewNewWindowRequested", handler);
webview.removeEventListener("MSWebViewNewWindowRequested", handler);

Event Information


Interface	NavigationEventWithReferrer
Synchronous	Yes
Bubbles	No
Cancelable	Yes

MSWebViewPermissionRequested

Indicates that content in the webview is trying to access functionality (such as geolocation, or pointer lock access) that normally requires end-user permissions. If no event handler is registered or if the event handler doesn't call eventArgs.permissionRequest.allow(), defer(), or deny(), then by default the permission request will be denied. If you need to decide if permission is allowed or denied asynchronously for instance if you need to prompt the user, use eventArgs.permissionRequest.defer(). The permission request will be deferred until you use webview.getDeferredPermissionRequestById or webview.getDeferredPermissionRequests and call allow() or deny() on the DeferredPermissionRequest with the corresponding id value.

webview.addEventListener("MSWebViewPermissionRequested", permissionRequestedEventArgs => {
    const permissionRequest = permissionRequestedEventArgs.permissionRequest;
    switch (permissionRequest.type) {
        case "geolocation":
        case "media":
        case "pointerlock":
        case "webnotifications":
        case "screen":
        case "immersiveview":
            if (permissionRequest.uri.startsWith("https://www.example.com/")) {
                // Implicitly trust particular URI
                permissionRequest.allow();
            }
            else if (permissionRequest.uri.startsWith("https://")) {
                // Defer the request so we can ask the user to allow or deny the request
                permissionRequest.defer();
                // Later we'll need to use webview.getDeferredPermissionRequestById for this
                // request and call allow or deny.
                promptUserForDeferredPermissionRequest(
                    permissionRequest.id,
                    permissionRequest.uri,
                    permissionRequest.type);
            }
            else {
                // Implicitly deny non-https URIs
                permissionRequest.deny();
            }
            break;

        case "unlimitedIndexedDBQuota":
        default:
            permissionRequest.deny();
            break;
    }
});

// addEventListener syntax
webview.addEventListener("MSWebViewPermissionRequested", handler);
webview.removeEventListener("MSWebViewPermissionRequested", handler);

Event Information


Interface	PermissionRequestedEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewProcessExited

Indicates that the webview component process crashsed. This is only relevant for an out-of-process WebView. See the Remarks section for how to create an out-of-process WebView as opposed to an in-process WebView. After this event fires, the corresponding WebView is put into a crashed state. Calling most WebView specific methods or accessing most WebView specific properties on a crashed WebView will throw an exception. To recover from this event, remove the crashed WebView from the DOM and replace it with a new WebView.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("MSWebViewProcessExited", handler);
webview.removeEventListener("MSWebViewProcessExited", handler);

Event Information


Interface	Event
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewWebResourceRequested

Raised when a page inside the webview element requests a resource.

// A handler that completes synchronously with a custom HTTP response built from a string.
function handlerWithSyncString(webResourceRequestedEventArgs) {
    // Only provide custom HTTP responses for particular HTTP requests
    if (webResourceRequestedEventArgs.args.request.requestUri.absoluteUri === "https://www.bing.com/") {
        const Http = Windows.Web.Http;
        // Create the custom response using a string
        webResourceRequestedEventArgs.args.response = new Http.HttpResponseMessage(Http.HttpStatusCode.ok);
        webResourceRequestedEventArgs.args.response.content = new Http.HttpStringContent("<H1>Example</H1>");
    }
});

// A more complicated handler that completes asynchronously with a custom HTTP response built from a stream.
function handlerWithAsyncStream(webResourceRequestedEventArgs) {
    // Only provide custom HTTP responses for particular HTTP requests
    if (webResourceRequestedEventArgs.args.request.requestUri.absoluteUri === "https://www.bing.com/") {
        // Take a deferral on the WebResourceRequested event so that we can create the custom HTTP response asynchronously.
        const deferral = webResourceRequestedEventArgs.args.getDeferral();

        // Use fetch to get a Blob of the content of the URI
        fetch("ms-appx:///replacement.html").then(fetchResponse => {
            return fetchResponse.blob();
        }).then(fetchResponseBlob => {
            const Http = Windows.Web.Http;
            webResourceRequestedEventArgs.args.response = new Http.HttpResponseMessage(
                Http.HttpStatusCode.ok);

            // Use Blob.msDetachStream to convert the Blob to a Windows.Storage.Streams.IInputStream
            webResourceRequestedEventArgs.args.response.content = new Http.HttpStreamContent(
                fetchResponseBlob.msDetachStream());

        }).finally(() => {
            // Use a finally call to complete the deferral so even if there is an error we will unblock the event.
            deferral.complete();
        });
    }
});
 
// addEventListener syntax
webview.addEventListener("MSWebViewWebResourceRequested", handler);
webview.removeEventListener("MSWebViewWebResourceRequested", handler);

Event Information


Interface	WebResourceRequestedEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewScriptNotify

Raised when a page inside the webview element calls the window.external.notify method. The window.external.notify method is only available to documents with URIs that match rules in the app's manifest's ApplicationContentUriRules or that has been programatically allowed via setting webview.settings.isScriptNotifyAllowed to true. Additionally window.external.notify is only available to the webview's top level document.

webview.addEventListener("MSWebViewScriptNotify", eventInfo => {
    console.log("The URI " + eventInfo.callingUri + 
        " has sent notification " + eventInfo.value);
});

// Allow the next URI to which we navigate access to window.external.notify
webview.settings.isScriptNotifyAllowed = true;
webview.navigate("https://example.com/");

webview.addEventListener("MSWebViewNavigationCompleted", () => {
    // Inject script to the webview that will send a notification back.
    const asyncOp = webview.invokeScriptAsync("eval", "window.external.notify('example notification')");
    asyncOp.start();
});

Event Information


Interface	ScriptNotifyEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewUnsafeContentWarningDisplaying

Occurs when the webview shows a warning page for content that was reported as unsafe by SmartScreen Filter.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("MSWebViewUnsafeContentWarningDisplaying", handler);
webview.removeEventListener("MSWebViewUnsafeContentWarningDisplaying", handler);

Event Information


Interface	Event
Synchronous	Yes
Bubbles	No
Cancelable	No

MSWebViewUnsupportedUriSchemeIdentified

Raised when there is navigation to an Uniform Resource Identifier (URI) that the webview does not support.

function handler(eventInfo) { /* Your code */ }
 
// addEventListener syntax
webview.addEventListener("MSWebViewUnsupportedUriSchemeIdentified", handler);
webview.removeEventListener("MSWebViewUnsupportedUriSchemeIdentified", handler);

Event Information


Interface	NavigationEvent
Synchronous	Yes
Bubbles	No
Cancelable	Yes

MSWebViewUnviewableContentIdentified

Raised when the webview attempts to navigate to web content with an unsupported content type. For example, PDFs are currently not supported by webview and navigations to PDF documents will not navigate and instead raise this event.

function handler(args) {
    if (args.mediaType === "application/pdf") {
        Windows.System.Launcher.launchUriAsync(new Windows.Foundation.Uri(args.uri));
    }
}

// addEventListener syntax
webview.addEventListener("MSWebViewUnviewableContentIdentified", handler);
webview.removeEventListener("MSWebViewUnviewableContentIdentified", handler);

Event Information


Interface	UnviewableContentIdentifiedEvent
Synchronous	Yes
Bubbles	No
Cancelable	No

Methods

addWebAllowedObject

Adds a native Windows Runtime object as a global parameter to the top-level document inside of a webview.

The object is not injected into the current document, but rather the next top-level document to which the webview navigates. The object is injected before any script from the HTML document runs so you can rely on the object in your document's global script.

You should use addWebAllowedObject either during an MSWebViewNavigationStarting event or before explicitly calling a navigate method. In these cases the object is injected into the document of the corresponding navigation. Calling it in some other context, you don't have a way to be certain into what document you'll inject your object.

Calling addWebAllowedObject multiple times in a row will inject multiple objects into the document. If you call it both before an explicit navigate call and then again during the corresponding MSWebViewNavigationStarting event, both calls will succeed and you'll have multiple objects injected. If you call multiple times with the same name parameter, the last call wins and the previous calls with that name are ignored.

If a navigate fails or is redirected, the addWebAllowedObject calls for that navigation are ignored. If you want to handle redirects you can subscribe to the MSWebViewNavigationStarting event watch for redirects and call addWebAllowedObject again according to whatever criteria is appropriate for your application. Similarly, once a document navigates away any objects injected via addWebAllowedObject for that document will not carry over to the next document and you'll need to explicitly call addWebAllowedObject if you want them to carry over.

If you call addWebAllowedObject for a document that has no WinRT access otherwise, or if it has AllowForWebOnly access via ApplicationContentUriRules then the object will only be injected if the object has the Windows.Foundation.Metadata.AllowForWeb metadata attribute. Otherwise injection will fail and an error will be reported to the JavaScript developer console. If called on a document that has full WinRT access, then the object will be injected regardless of the AllowForWeb attribute.

Additionally, the object must implement the IAgileObject interface. This is because the XAML and HTML webview elements run on their app's ASTA view threads and the WebView's JavaScript thread is a different ASTA thread and we want to encourage app developers to ensure their object can run on the JavaScript thread without blocking the app view thread if possible.

The name parameter must be a valid JavaScript property name otherwise the call will fail silently. If the name is of a property that already exists on the global object then that property is overwritten if the property is configurable. Non-configurable properties on the global object are not overwritten and the addWebAllowedObject call fails silently. JavaScript properties created via addWebAllowedObject are writable, configurable, and enumerable.

let name = "exampleProperty";
webview.addWebAllowedObject(name, applicationObject);
webview.navigate("https://example.com/"); // applicationObject will be available as window.exampleProperty on https://example.com

Parameters

name

Type: String
The name of the object to expose to the document in the webview.

applicationObject

Type: Object
The object to expose to the document in the webview.

Return value

This method does not return a value.

Additional features and requirements


Minimum supported client	Windows 10 (Windows Store apps only)
Minimum supported server	None supported
Minimum supported phone	None supported

buildLocalStreamUri

Creates a URI that you can pass to navigateToLocalStreamUri.

var string = webview.buildLocalStreamUri(contentIdentifier, relativePath);

Parameters

contentIdentifier

Type: String
A unique identifier for the content the URI is referencing. This defines the root of the URI.

relativePath

Type: String
The path to the resource, relative to the root.

Return value

Type: String

The URI created by combining and normalizing the contentIdentifier and relativePath.

Example

The following example illustrates a typical use case.

var webview = document.createElement("x-ms-webview"); //Instantiate the webview element
var localStreamUri = webview.buildLocalStreamUri(contentIdentifier, relativePath); //Create URI to pass to navigateToLocalStreamUri method
webview.navigateToLocalStreamUri(localStreamUri, streamResolver); //Load the local web content

capturePreviewToBlobAsync

Creates an image of the current webview element and write it to the specified image element.

var capturePreviewToBlobAsync = webview.capturePreviewToBlobAsync();

Parameters

This method has no parameters.

Return value

Type: MSWebViewAsyncOperation

An MSWebViewAsyncOperation object that, when it completes, provides a Blob object that contains the image. When using capturePreviewToBlobAsync, you need to define success and error handlers after defining the operation. After applying the event handlers, call the start method on the MSWebViewAsyncOperation object to execute the operation.

captureSelectedContentToDataPackageAsync

Important

This method has been deprecated and has a known issue. Avoid using this method in your production code.

Asynchronously gets a DataPackage that contains the selected content within the webview.

var msWebViewAsyncOperation = webview.captureSelectedContentToDataPackageAsync();

Parameters

This method has no parameters.

Return value

Type: MSWebViewAsyncOperation

An MSWebViewAsyncOperation object that, when it completes, provides a DataPackage object that contains the image. When using captureSelectedContentToDataPackageAsync, you need to define success and error handlers after defining the operation. After applying the event handlers, call the start method on the MSWebViewAsyncOperation object to execute the operation.

 var operation = webview.captureSelectedContentToDataPackageAsync();
    operation.oncomplete = function () {
        // operation.result is a package object that contains the selected data.
        var url = URL.createObjectURL(operation.result, { oneTimeOnly: true });
        // After converting the package to a URI, put it in an image element.
        document.getElementById('webviewPreview').src = url;
    };
    operation.start();

invokeScriptAsync

As an asynchronous action, executes the specified script function from the currently loaded HTML, with specific arguments.

webview.invokeScriptAsync(functionName, ...args)

Parameters

functionName

Type: String
The name of the function to invoke. This is a property name on the global window object of the WebView's top level document. This can be a built-in global function like eval or open, or it can be a script defined function on the global window object. Only functions in the top level document of the WebView may be invoked.

args

Type: String
Optional string parameters to pass to the invoked function. After functionName, any additional parameters to invokeScriptAsync are strings passed to the invoked function.

Return value

Type: MSWebViewAsyncOperation

When using invokeScriptAsync, you need to define success and error handlers after defining the operation. After applying the event handlers, call MSWebViewAsyncOperation.start to execute the operation. If the MSWebViewAsyncOperation's complete event fires then the MSWebViewAsyncOperation's result property is the string return value from invoking the function. Using the invoked function's return value allows for the WebView content to communication synchronously back to the WebView host. To instead have the WebView content communicate asynchronously back to the WebView host see the MSWebViewScriptNotify event. If the function invoked throws an unhandled exception then the MSWebViewAsyncOperation's error event will fire.

const functionName = "eval";
const args = ["'Current URL: ' + document.location.href"];

const asyncOp = webview.invokeScriptAsync(functionName, ...args);

asyncOp.onerror = () => console.error("Error: " + asyncOp.error);
asyncOp.oncomplete = () => console.log("Result: " + asyncOp.result); // Logs 'Current URL: about:blank'
asyncOp.start();

getDeferredPermissionRequests

Returns a list of deferred permission requests issued by content in the webview control.

var sequence<PermissionRequest> = x-ms-webview.getDeferredPermissionRequests();

Parameters

This method has no parameters.

Return value

Type: DeferredPermissionRequest

The specified deferred permission request.

Additional features and requirements


Minimum supported client	Windows 10 (Windows Store apps only)
Minimum supported server	None supported
Minimum supported phone	None supported

getDeferredPermissionRequestById

Returns the specified deferred permission request.

var deferredPermissionRequest = x-ms-webview.getDeferredPermissionRequestById(id);

Parameters

Type: unsigned long
The ID of the deferred permission request you wish to get.

Return value

Type: DeferredPermissionRequest

The specified deferred permission request.

Additional features and requirements


Minimum supported client	Windows 10 (Windows Store apps only)
Minimum supported server	None supported
Minimum supported phone	None supported

goBack

Navigates the webview to the previous page in the navigation history.

webview.goBack();

Parameters

This method has no parameters.

Return value

This method does not return a value.

goForward

Navigates the webview to the next page in the navigation history.

webview.goForward();

Parameters

This method has no parameters.

Return value

This method does not return a value.

navigate

Loads the HTML content at the specified Uniform Resource Identifier (URI).

webview.navigate(uri);

Parameters

uri

Type: String
The URI to load.

Return value

This method does not return a value.

navigateFocus

Navigates focus onto the webview. Fires the webview's top level document's window's navigatingfocus event. The FocusNavigationEvent args used in the navigatingfocus event match the parameters provided to navigateFocus except the origin parameters are translated from the host document's coordinate space to the coordinate space of the webview's top level document. See the webview departingFocus event and corresponding window.departFocus method for transferring focus from the webview to the host. See the TVJS's Direction Navigation library for an example of an implementation of focus navigation via keyboard or gamepad that uses this method.

const activeElementBounds = document.activeElement.getBoundingClientRect();
const origin = { 
    originLeft: activeElementBounds.left,
    originTop: activeElementBounds.top,
    originWidth: activeElementBounds.width,
    originHeight: activeElementBounds.height
};
webview.navigateFocus(navigationReason, origin);

Parameters

navigationReason

Type: String
The reason for the navigation. The value should be either "left", "up", "right", or "down". It is the direction in which focus is moving away from the currently focused element.

origin

Type: Object
The origin of the navigation. This is a JavaScript object with properties "originLeft", "originTop", "originWidth", and "originHeight". These values should describe the position and size of the currently focused element away from which focus is moving.

Return value

This method does not return a value.

navigateToLocalStreamUri

Loads local web content at the specified URI using a UriToStreamResolver.

webview.navigateToLocalStreamUri(source, streamResolver);

Parameters

source

Type: String
An ms-local-stream URI identifying the local HTML content to load. Create this string using buildLocalStreamUri.

streamResolver

Type: any
A resolver that converts the URI into a stream to load.

Return value

This method does not return a value.

navigateToString

Loads the specified HTML content as a new document.

webview.navigateToString(contents);

Parameters

contents

Type: String
The HTML content to display.

Return value

This method does not return a value.

navigateWithHttpRequestMessage

Navigates the webview to a Uniform Resource Identifier (URI) with a POST request and HTTP headers.

webview.navigateWithHttpRequestMessage(requestMessage);

Parameters

requestMessage

Type: HttpRequestMessage
The details of the HTTP request.

Return value

This method does not return a value.

Remarks

Warning

If you add additional headers to this request, such as authentication credentials, remember that those headers will also be included with any subsequent child requests. Use caution to prevent accidental disclosure of confidential or personal information.

refresh

Reloads the current content in the webview.

webview.refresh();

Parameters

This method has no parameters.

Return value

This method does not return a value.

stop

Halts the current webview navigation or download.

webview.stop();

Parameters

This method has no parameters.

Return value

This method does not return a value.

Properties

canGoBack

Gets a value that indicates whether the webview can navigate backward.

This property is read-only.

var canGoBack = webview.canGoBack;

Property value

Type: Boolean

True if the webview can navigate backward; otherwise, false.

canGoForward

Gets a value that indicates whether the webview can navigate forward.

This property is read-only.

var canGoForward = webview.canGoForward;

Property value

Type: Boolean

True if the webview can navigate forward; otherwise, false.

containsFullScreenElement

Gets a value that indicates whether the webview contains an element that supports full screen. See the MSWebViewContainsFullScreenElementChanged event for more info.

This property is read-only.

var containsFullScreenElement = webview.containsFullScreenElement;

Property value

Type: Boolean

True if the webview contains an element that supports full screen; otherwise, false.

documentTitle

Gets the title of the page currently displayed in the webview.

This property is read-only.

var documentTitle = webview.documentTitle;

Property value

Type: String

The page title.

height

Gets or sets the height of the webview.

var height = webview.height;
webview.height = height;

Property value

Type: Number

The height of the webview.

process

Gets the webview process.

This property is read-only.

var process = webview.process;
webview.process = process;

Property value

Type: MSWebViewProcess

settings

Gets a MSWebViewSettings object that contains properties to enable or disable webview features.

This property is read-only.

var settings = webview.settings;
webview.settings = settings;

Property value

Type: MSWebViewSettings

A MSWebViewSettings object that contains properties to enable or disable webview features.

src

Gets or sets the Uniform Resource Identifier (URI) source of the HTML content to display in the webview control.

var src = webview.src;
webview.src = src;

Property value

Type: String

The URI source of the HTML content to display in the webview control.

width

Gets or sets the width of the webview.

var width = webview.width;
webview.width = width;

Property value

Type: Number

The width of the webview.

Sdílet prostřednictvím

WebView (EdgeHTML) for Windows 10 apps

Syntax

Remarks

WebView versus iframe

Printing

Service workers

Threading model and reliability

WinRT API access

AppCache storage limitations

Events

departingFocus

Event Information

MSWebViewContainsFullScreenElementChanged

Event Information

MSWebViewContentLoading

Event Information

MSWebViewDOMContentLoaded

Event Information

MSWebViewFrameContentLoading

Event Information

MSWebViewFrameDOMContentLoaded

Event Information

MSWebViewFrameNavigationCompleted

Event Information

MSWebViewFrameNavigationStarting

Event Information

MSWebViewLongRunningScriptDetected

Event Information

MSWebViewNavigationCompleted

Event Information

MSWebViewNavigationStarting

Event Information

MSWebViewNewWindowRequested

Event Information

MSWebViewPermissionRequested

Event Information

MSWebViewProcessExited

Event Information

MSWebViewWebResourceRequested

Event Information

MSWebViewScriptNotify

Event Information

MSWebViewUnsafeContentWarningDisplaying

Event Information

MSWebViewUnsupportedUriSchemeIdentified

Event Information

MSWebViewUnviewableContentIdentified

Event Information

Methods

addWebAllowedObject

Parameters

Return value

Additional features and requirements

buildLocalStreamUri

Parameters

Return value

Example

capturePreviewToBlobAsync

Parameters

Return value

captureSelectedContentToDataPackageAsync

Parameters

Return value

invokeScriptAsync

Parameters

Return value

getDeferredPermissionRequests

Parameters

Return value

Additional features and requirements

getDeferredPermissionRequestById

Parameters

Return value

Additional features and requirements

goBack

Parameters

Return value

goForward

Parameters