Microsoft runtime error : $ is undefined

[woodson]

Hi,
    i am new for Jquery. i would like to implement the JQueryAjax.see the below code i am using
$.ajax({
     url: 'myPage.php',
     success: function(response) {
        alert(response);
     },
     error: function(xhr) {
        alert('Error!  Status = ' + xhr.status);
     }
 });
But i am getting the error like
Microsoft runtime error : $ is undefined.. thanks in advance