The image probably isn't loaded by that time. I mean, it's probably a couple milliseconds, if that, between when you assign that src and when you ask for the width and height.

offButton.src = “images/blueButton.gif” onButton.src = “images/redButton.gif” } ... such as moving the cursor over an image, JavaScript will catch it and do whatever you’ve asked it to do.

button1Red.src = “images/redButton1.gif” button1Blue.src = “images ... As always, only use this code if the browser you’re designing for supports image manipulation via JavaScript ...