title: how to get data from tag of html
body: <p>I have this HTML snippet here:</p>
  
  <pre><code>&lt;tr class="newRow"&gt;
    &lt;td class="doc" ids="1"&gt;ABC&lt;/td&gt;
    &lt;td class="doc" ids="2"&gt;EFG&lt;/td&gt;
    &lt;td class="doc" ids="1"&gt;ABC&lt;/td&gt;
    &lt;td class="doc" ids="3"&gt;HIJ&lt;/td&gt;
  &lt;/tr&gt;
  </code></pre>
  
  <p>And here is my script:</p>
  
  <pre><code>var formDoc = $.map($('.doc'), function(e) {
      return e.attr("ids");
  });
  alert(formDoc);
  </code></pre>
  
  <p>It only returns empty. Could you give me an advise to solve my issue?</p>