[求解]一个页有两个验证码 同时刷新问题!

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><html>
<head>
    <title>Untitled</title>
</head><body>
<span id=abc >
<img src="http://www.cnbeta.com/validate1.php" onclick="a(this);">
</span>
<span id=bak>
<img id=abc src="http://www.cnbeta.com/validate1.php">
</span>
<script>
function a(obj){
obj.src=obj.src+'?'+(new Date).getTime()
var idx = document.getElementById('abc').cloneNode(true);
var newidx = document.getElementById('bak');
newidx.innerHTML='';
newidx.appendChild(idx);
}
</script>
</body>
</html>