recalculateLayout Method
Recalculates the layout of the ReportViewer.
$find(viewerId).recalculateLayout();
Remarks
If the size of the ReportViewer changes due to a change in its containing element, use this method to recalculate its layout to use more or less space on the Web page, depending on the change. For example, if the ReportViewer control is configured to fill up a table cell, the ReportViewer may not be automatically resized or resized correctly if the size of the containing table cell changes. You should call this method after such actions. You do not need to call this method if the size of the browser window changes.
When the Web page is performing a postback or the client-side control is loading content, accessing the methods or properties will cause an exception with the message: "The report or page is being updated. Please wait for the current action to complete." Use the isLoading property to check whether the report or page is being updated and whether you can access the methods and properties.