function validate_required(field,alerttxt)
{
with (field)
{
if (value==null||value=="")
  {alert(alerttxt);return false;}
else {return true}
}
}

function validate_form(thisform)
{
with (thisform)
{

var regexp = /^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/;
email_val = document.SubmitForm.email.value;

if (validate_required(CardHolder,"Name must be filled!")==false)
  {CardHolder.focus();return false;}

if (!checkForm(thisform))
return false;

if (validate_required(CardNo,"Card Number must be filled!")==false)
  {CardNo.focus();return false;}
  
  if (validate_required(email,"Email must be filled!")==false)
  {email.focus();return false;}
  

		if(email_val.search(regexp) == -1){
		alert("Enter valid Email address");
		   email.focus();return false;
			}




}


}


		
function checkForm(form)  
{ 
  var checked = false; 
  var buttons = form.elements.Card_Type; 
  for (var i=0; i<buttons.length; i++)  
  {  
    if (buttons[i].checked) {  
      checked = true; 
       
    }  
   } 
   if(!checked) 
{
     alert("Please select Card Type");  
   return false; 
}
else
{
return true;
}
}