By default, two Web pages in different frames are prevented from accessing each other's content using script; even www.microsoft.com and msdn.microsoft.com are, in this instance, considered different domains. To enable cross-frame scripting for pages from the same top-level domain, you can assign a new value to the HtmlDocument.Domain property. In the pervious URL example, setting HtmlDocument.Domain to microsoft.com would allow both pages to communicate with one another.

Strings assigned to the HtmlDocument.Domain property must be valid top-level domains. In the previous URL example, you can set HtmlDocument.Domain to microsoft.com, but not to .com, which would enable any page on the Internet to script a page's contents.

You cannot use the HtmlDocument.Domain property to enable cross-frame scripting for pages accessed using two different protocols. If one frame in your page comes from a Web server (the http:// protocol) and another comes from the file system (the file://) protocol, they will not be able to communicate with one another regardless of the value of the HtmlDocument.Domain property.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
Assembly Versions: 2.0.0.0