Syntax
window.frames["frameName"].length window.frames[num].length
The length property contains the number of frame instances in a document created with the tag.
<html> <script language="JavaScript"> <!-- for(var i = 0; i <= window.frames.length; i++){ newWin.document.write("The name of frame #" + i); newWin.document.write(" is " + window.frames[i].name + "<br>"); } --> </script> </html>