function validate_email(entered,alertbox) {

   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var address = entered.value;
   if(reg.test(address) == false) {
     if (alertbox!="") alert(alertbox,entered);
      return false;
   }
}
function IsNumeric(strString)
{
   var strValidChars = "0123456789-+(). ";
   var strChar;
   var blnResult = true;
   if (strString.length == 0) return false;

   for (i = 0; i < strString.length && blnResult == true; i++)
      {
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1)
         	{
        	 blnResult = false;
         	}
      }
   return blnResult;
}