call ajax on form submit

<script>
$("#contactForm").submit(function(e) {
//---------------^---------------
e.preventDefault();

var name =$("#name").val();
var surname =$("#surname").val();
var email =$("#email").val();
var dataString = "name="+name+"&surname="+surname+"&email="+email;
$.ajax({
  type: "POST",
  url: "send.php",
  data: dataString,
  cache: false,
  success: function(result){
if(result==1){
$("#mess_sucess").html('');
$('#mess_sucess').show();
var mass='<span style="color:red;margin-bottom: 20px;">Thanks. Your Request Submitted Successfully!</span>';
$('#mess_sucess').html(mass);
document.getElementById('download').click();

}else{
$("#mess_sucess").html('');
$('#mess_sucess').show();
var mass='<span style="color:red;margin-bottom: 20px;">Thanks. Your Request Not Submitted Successfully!</span>';
$('#mess_sucess').html(mass);

}

  }
});

});
</script>