Why am I getting undefined is not a function when using jquery? HTML

more code here...

&lt;script type="text/javascript" src="//code.jquery.com/jquery-1.10.2.min.js"&gt;&lt;/script&gt;
&lt;script type="text/javascript" src="https://example.com/sites/all/modules/ac_modules/ac_exercise/ac_exercise.js?nkuo2r"&gt;&lt;/script&gt;


more code here...

&lt;div class="form-item form-type-textfield form-item-time-start"&gt;
  &lt;label for="edit-time-start"&gt;Time Start &lt;/label&gt;
 &lt;input type="text" id="edit-time-start" name="time_start" value="11:28:12" size="4" maxlength="8" class="form-text" /&gt;
&lt;/div&gt;


more code here...

Javascript - ac_exercise.js

$(document).ready(function(){ 
  $("#edit-time-start").on("change paste keyup", function() {
     alert($(this).val()); 
  });
});


In Chrome's console I get the following error:
Uncaught TypeError: undefined is not a function - ac_exercise.js?nkuo2r:1 which is this line of code:

$(document).ready(function(){
(function ($) {
  $(document).ready(function(){

  your code here

  });
})(jQuery);