title: How can I disable bootstrap dropdown list
body: <p>I made a dropdown list using bootstrap.Dynamically I want to disable and enable the dropdown list.</p>
  
  <p>html code:</p>
  
  <pre><code>  &lt;div class="span3 offset1"&gt;
          &lt;select name="primary" class="select-block" id="select_alert" style="display: none;"&gt;
              &lt;option "selected"=""&gt;Choose Alert T&lt;/option&gt;                         
  
  
      &lt;option value="T1"&gt;T1&lt;/option&gt;
  
      &lt;option value="T2"&gt;T2&lt;/option&gt;
  
      &lt;option value="T3"&gt;T3&lt;/option&gt;
  
      &lt;option value="T4"&gt;T4&lt;/option&gt;
  
  &lt;/select&gt;
  &lt;div class="btn-group select select-block"&gt;
    &lt;i class="dropdown-arrow dropdown-arrow-primary"&gt;&lt;/i&gt;
    &lt;button class="btn dropdown-toggle clearfix btn-primary" data-toggle="dropdown" id="select_alert"&gt;
      &lt;span class="filter-option pull-left"&gt;Choose Alert T&lt;/span&gt;&amp;nbsp;
      &lt;span class="caret"&gt;&lt;/span&gt;
    &lt;/button&gt;
    &lt;ul class="dropdown-menu dropdown-primary" role="menu"&gt;
      &lt;li rel="0" class="selected"&gt;
        &lt;a tabindex="-1" href="#" class=""&gt;
          &lt;span class="pull-left"&gt;Choose Alert T&lt;/span&gt;
        &lt;/a&gt;
      &lt;/li&gt;
      &lt;li rel="1"&gt;
        &lt;a tabindex="-1" href="#" class=""&gt;
          &lt;span class="pull-left"&gt;T1&lt;/span&gt;
        &lt;/a&gt;
      &lt;/li&gt;
      &lt;li rel="2"&gt;
        &lt;a tabindex="-1" href="#" class=""&gt;
          &lt;span class="pull-left"&gt;T2&lt;/span&gt;&lt;/a&gt;
      &lt;/li&gt;
      &lt;li rel="3"&gt;
        &lt;a tabindex="-1" href="#" class=""&gt;
          &lt;span class="pull-left"&gt;T3&lt;/span&gt;
        &lt;/a&gt;
      &lt;/li&gt;
      &lt;li rel="4"&gt;
        &lt;a tabindex="-1" href="#" class=""&gt;
          &lt;span class="pull-left"&gt;T4&lt;/span&gt;
        &lt;/a&gt;
      &lt;/li&gt;
    &lt;/ul&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>some times I want to disable and sometimes I want to enable.So How can I do this.
  In this I have 2 more dropdown elemnts.All are placed in singlw <code>div</code> tag.Here I didn't mention that <code>div</code> tag id name.I just putted single dropdown element  code.</p>