title: What is 'for' used for in bootstrap form label?
body: <p>I don't know the meaning of <code>for="inputEmail3"</code>, seems its same as id, what is it for? Can I just remove <code>for="inputEmail3"</code> ?</p>
  
  <pre><code>&lt;form&gt;
    &lt;div class="form-group row"&gt;
      &lt;label for="inputEmail3" class="col-sm-2 form-control-label"&gt;Email&lt;/label&gt;
      &lt;div class="col-sm-10"&gt;
        &lt;input type="email" class="form-control" id="inputEmail3" placeholder="Email"&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  </code></pre>