Specifying a Rendering Format in a URL
You can optionally specify the format in which to render a report by using the Format parameter. You must use the rs: parameter prefix with this parameter.
Valid values for this parameter are based on the report rendering extensions that are installed on the report server being accessed. You can use the ListExtensions method, provided by the SQL Server Report Server Web service, to determine which rendering extensions are installed on a particular instance of the report server. Common extensions are HTML3.2, HTML4.0, HTMLOWC, MHTML, IMAGE, EXCEL, CSV, PDF, XML, and NULL. If a specified rendering extension is not installed on the report server, the report is not rendered and an error is generated and displayed in the browser.
If you do not include the Format parameter as part of the URL, the report server detects the browser and renders the report in the appropriate HTML format.
Example
The following example renders a report in HTML 4.0 format:
https://servername/reportserver?/Sales/YearlySalesSummary&rs:Format=HTML4.0&rs:Command=Render