function submitForm() {
var form = document.form1;
var valid = true;
var invalidFields = "";
var emailvalid = true;
var mailreg = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*\.(\w{2,})$/;

if(form.First_Name.value==""){
 valid=false; invalidFields+="First Name\n";
}

if(form.Last_Name.value==""){
valid=false; invalidFields+="Last Name\n";
}

if(form.Email.value == ""){
  valid = false;
  invalidFields += "Email\n";
  }else if(form.Email.value.search(mailreg) == -1){
  emailvalid = false;
  alert("The email address you entered is invalid. \n");
  return false;
  }

if(!emailvalid) {
valid = true;
return false;
}

if(!valid){
alert("Please fill in the following fields: \n" + invalidFields + " \n");
return false;
}

if(valid){
  document.form1.submit();
  }
}