title: Jquery : how to add <li> in an existing <ul> with json data
body: <p>I have code that looks like this:</p>
  
  <pre><code>&lt;div id="tags"&gt;
    &lt;ul&gt;
    &lt;/ul&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>and I'd like to append some items to the list using json data</p>
  
  <pre><code> $.getJSON("data.json", function (data) {
              var html = '';
              var len = data.tags.length;
              for (var i = 0; i &lt; len; i++) {
                  html += '&lt;li&gt;&lt;a href="#"&gt;' + data.tags[i].tag + '&lt;/a&gt;&lt;/li&gt;';
              }
  
              $("#tags ul").append(html);
  
  
          })
          .done(function () {
              console.log("second success");
             })
         .fail(function(err){console.log(err)});
  </code></pre>
  
  <p>but nothing happens , where is my mistake?</p>