Changing an Image Using the onClick Event Handler

<SCRIPT>

var imageURL = "images/clock.jpg";

if (document.images) {
     var clock = new Image();
     clock.src = "images/clock.jpg";

     var cup = new Image();
     cup.src = "images/cup.gif";
}

function changeImage() {
     if (document.images) {
          if (imageURL == "images/cup.jpg") imageURL = "images/clock.jpg";
          else imageURL = "images/cup.jpg";

         document.myImage.src = imageURL;
     }
}

</SCRIPT>

<FORM>
     <INPUT TYPE="Button" VALUE="Change the image source" onClick="changeImage();">
</FORM>

<IMG SRC="clock.jpg" NAME="myImage">