//验证码 
function changeAuthCode() { 
    var num =     new Date().getTime();
    var rand = Math.round(Math.random() * 10000);
    num = num + rand;
    $('#ver_code').css('visibility','visible');
    if ($("#vdimgck")[0]) {
        $("#vdimgck")[0].src = "../include/vdimgck.php?tag=" + num; 
 }
    return false;    
}
</script>