function refreshcaptcha(imgid,siteurl)
 {
    
    var img = document.getElementById(imgid);
    img.src = siteurl + "/captchapage.aspx?d=" + getCurTime();
    
}
function getCurTime() {
    var d = new Date();
    var curr_hour = d.getHours();
    var curr_min = d.getMinutes();
    var curr_sec = d.getSeconds();
    var curr_msec = d.getMilliseconds();
    return curr_hour + "_" + curr_min + "_" + curr_sec + "_" + curr_msec;
}
 function isNumberKey(evt)
{
    var charCode = (evt.which) ? evt.which : event.keyCode
    if (charCode > 31 && (charCode < 48 || charCode > 57))
        return false;
         return true;
}