var submitted = 0;
  
  function formvalidation(form) 
  {
     if (submitted) 
     {
       submitted = 0;
       return false;
     }
     
     if (document.getElementById("sFirstName").value == "")
     {
       alert("First Name Required");
       document.getElementById("sFirstName").focus();
       return false;
     }
     
     if (document.getElementById("sEmailAddress").value == "")
     {
       alert("Email Address Required");
       document.getElementById("sEmailAddress").focus();
       return false;
     }
     
     if(!validateEmail(document.getElementById("sEmailAddress").value, 1, 0)) 
     {
       alert("Invalid Email Address");
       document.getElementById("sEmailAddress").focus();
       return false;
     }
     
     if (!submitted) 
     {
       submitted = 1;
       form.submit();
     }
}