Return Value
Boolean: true if in strict mode; false otherwise
This method is used in support of Microsoft Visual Studio 2005.
Strict Mode is sometimes called strict compliance mode or standards mode or strict rendering mode and refers to the use of a valid DOCTYPE (document type) declaration, as opposed to quirks mode for an incomplete or outdated DOCTYPE. A browser renders the page in strict mode when it detects the presence of a valid up-to-date XML DOCTYPE.
Standards mode may be as good a description as strict mode, since it means strict compliance with the standards, and not strictly being tied to a particular DOCTYPE.
For more information on strict mode, refer to the Microsoft documentation, especially the Internet Explorer documentation.