I'm a newbie programmer, and I've been following an Instagram search tutorial I found online. Inspired by it, I've decided to try building it myself to learn jQuery. Problem is, I can't get the example to work. I can display the default 'cat' search, but when I try searching through the web form, I get no results—no errors, nothing. I'm really stuck and feel like I’m missing something simple. Any help would be greatly appreciated!
Here is js code:
var Instagram = {};
(function () {
    function toScreen(photos) {
        $.each(photos.data, function (index, photo) {
            photo = "<div class='photo'>" +
                "<a href='" + photo.link + "' target='_blank'>" +
                "<img class='main' src='" + photo.images.low_resolution.url + "' width='250'  height='250' />" +
                "</a>" +
                "<img class='avatar' width='40' height='40' src='" + photo.user.profile_picture + "' />" +
                "<span class='heart'><strong>" + photo.likes.count + "</strong></span>" +
                "</div>";
            $('div#photos-wrap').prepend(photo);
        });
    }
    function search(tag) {
        var url = "https://api.instagram.com/v1/tags/" + tag + "/media/recent?callback=?&client_id=XXXXXXXXXXXXXXXXXX"
        $.getJSON(url, toScreen);
    }
    $(function () {
        $('form#search button').click(function () {
            var tag = $('input.search-tag').val();
            Instagram.search(tag);
        });
        Instagram.search('cats');
    });
    Instagram.search = search;
})();
and the HTML
    <!DOCTYPE html>
    <html>
    <head>
<title></title>
<script src='https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js'  type='text/javascript' charset='utf-8'></script><script src='javascripts/application.js' type='text/javascript' charset='utf-8'></script>
<link href="stylesheets/application.css" media="screen" rel="stylesheet" type="text/css" />
    </head>
    <body>
    <div id='photos-wrap'>
      <form id='search'>
       <button type='submit' id='search-button' tabindex='2'>
         <span class='button-content'>Search</span>
      </button>
     <div class='search-wrap'>
       <input class='search-tag' type='text' tabindex='1' />
      </div>
   </form>
  </div>
     </body>
     </html>