// this is the id of the form
$("#idForm").submit(function(e) {
var url = "path/to/your/script.php"; // the script where you handle the form input.
$.ajax({
type: "POST",
url: url,
data: $("#idForm").serialize(), // serializes the form's elements.
success: function(data)
{
alert(data); // show response from the php script.
}
});
e.preventDefault(); // avoid to execute the actual submit of the form.
});