The length property contains the number of objects that are in the images[] array.
<html> <h2>A Circle</h2> <img src="http://www.java2java.com/style/logo.png"> <h2>A Square</h2> <img src="http://www.java2java.com/style/logo.png"><br> <script language="JavaScript"> <!-- document.write(document.images.length," image objects."); --> </script> </html>