function payment_invoice(f)
	{		

req=new Array();
req_desc=new Array();

req[0]="invoice";
req_desc[0]="Invoice";


req[1]="amount";
req_desc[1]="Amount";

req[2]="fullname";
req_desc[2]="Full name";

req[3]="company";
req_desc[3]="Company";


req[4]="email";
req_desc[4]="Email";


req[5]="phone";
req_desc[5]="Phone";

req[6]="cardnumber";
req_desc[6]="Card Number";

req[7]="cardexpiry";
req_desc[7]="Card Expiry";

req[8]="cardcvv";
req_desc[8]="Card cvv";

req[9]="cardname";
req_desc[9]="Card name";



for(var i=0 ; i < req.length; ++i)
	{
		if( eval("f."+req[i]).value == "" )
		{	
			eval("f." + req[i]).focus();
			eval("f." + req[i]).style.background.color = "#333333";
			alert(  req_desc[i] + " is a required field. Please fill it.");
			return false;
		}		
	}
	
	if(f.cardtype.selectedIndex==0)
	{
	alert("Please Select Card type");
	f.cardtype.focus();
	return false;		
	}
	

if (!(/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(pi.email.value)))
	{
	alert("Enter Valid Email addresss");
	pi.email.select();
	return false;
	}	 	
alert("Form is submitting");		
		
	}