Required Fields With PayPal button

[sss_1234]

Hi there,

I am using the following function to check for a required field:

function verify() {
var themessage = "You are required to complete the following fields: ";
if (document.order.tandc.value=="") {
themessage = themessage + " - Terms & Conditions";
}
//alert if fields are empty and cancel form submit
if (themessage == "You are required to complete the following fields: ") {
document.order.action=insertstandard.php;
}
else {
alert(themessage);
return false;
   }
}

The code is checking for the required field, and displays the alert box however when the user clicks ok, the form is still processed!

Any help with this much appreciated.

Kind regards, Mike