I'm aware of how the cache can prevent images from updating, this is over come by appending random characters to the image. That's what I've done below. Yet it doesn't seem to function in IE. I need the value in id to be passed to verify-image.php. I have tried swapping the placement of ID and rnum but that had no effect. Do you guys have any ideas?
var id = document.form1.id_check.value;
var rnum = parseInt(Math.random()*10);
img = document.getElementById('Captcha');
img.src = "./includes/verify-image.php?"+rnum+"&id="+id;