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How to use F12 Developer Tools to Debug your Webpages

This content refers to an older version of F12 developer tools. Please visit our latest F12 tools documentation.

The F12 tools is a suite of on-demand tools that is built into every installation of Windows Internet Explorer 9. F12 tools is available anytime, on any page, and enables website developers to quickly debug JavaScript, HTML, and Cascading Style Sheets (CSS), as well track down performance problems on a webpage or network.

In this section

Topic Description

Introduction to F12 Developer Tools

F12 tools is a suite of tools to help you build and debug your webpage.

Getting Started with the F12 Developer Tools

The F12 tools menus and buttons provide page and visual tools to help you navigate the tool suite. Within the tools, you can create report lists of all the links in your document, change document modes, or visually outline a specific element on a page.

Using the F12 Tools Console to View Errors and Status

The F12 tools console commands let you receive error messages from Internet Explorer 9, as well as send your own messages back from your code without having to break the flow of your execution.

F12 tools console error messages

The F12 tools console can report error and informational messages that occur during runtime. This article describes the error messages and offers suggestions for how to fix the errors.

Using the F12 Developer Tools to Debug JavaScript Errors

F12 tools enables web developers to quickly debug JavaScript code without leaving the browser.

Using F12 Developer Tools to Debug HTML and CSS

The F12 tools can help you find and fix errors in HTML and CSS code that might otherwise be hard to find in your source code.

Using the Profiler Tool to analyze the performance of your code

The F12 tools provide a built-in script profiler that enables you to analyze the performance of JavaScript code running in Internet Explorer 9. This topic explains the features of this tool and how you can use it to check the performance of your scripts.


Find the current F12 Developer Tools documentation on the Microsoft Edge browser portal

Internet Explorer 9 Samples and Tutorials