$ {document).ready不起作用

When I click the submit button, why <div> does not show 'Loading...'? I have very less knowledge about jQuery and Ajax. Please help me with simple explanations. Thanks

    <head>
  <script type="text/javascript" 
     src="http://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>

  <script>
    $(document).ready( function(e) {

            $(".frmUpload").on('submit',(function(e) {
                    e.preventDefault();
                    $(".upload-msg").text('Loading...');

            });
    });
  </script>
</head>

<h1>Ajax Image Upload</h1>
        <form action="" method="post" class="frmUpload">
            <input type="file" name="photoUpload" id="ajaxUpload">
            <input type="submit" value="UPLOAD">
        </form>
        <div class="img-preview"></div>
        <div class="upload-msg"></div>

You've missed an ending ).

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

        $(".frmUpload").on('submit',(function(e) {
                e.preventDefault();
                $(".upload-msg").text('Loading...');

        }));
});

Works better, notice the })). You don't strictly need the ( before the function in 'submit', (function , so you can alternatively remove that one.