deprecated; do not use
document.clear() temporarily erases the specified document (i.e., it clears the window or frame that contains document). This method does not actually remove the contents of the document, and if the window is covered and then uncovered, for example, the document will be redrawn. This is unusual and generally undesirable behavior, and the use of the clear() method is not recommended.
Furthermore, Internet Explorer 3.0 defines this function in an compatible way. On that platform, the clear() method is simply a synonym for Document.open().