title: autohide text box when a particular option is selected from combo
body: <p>I have one combo box which displays a text box when 2nd or 3rd option is selected, but how to hide that text box when first option is selected?</p>
  
  <pre><code>$("#combo").change(function () {
          $.getJSON('combo.jsp', {
              comboname: this.value
          }, function (data) {
              if(data.isTrue){
              $("#textbox").empty().append("&lt;input type='text' id='text1'/&gt;");// display an empty text box
                     }
                     else{
                         // how to clear that text box and hide it?
                     }
          });
      });
  </code></pre>
  
  <p>html</p>
  
  <pre><code>&lt;select id="combo" name="comboname"&gt;
  &lt;option value="_"&gt;&lt;/option&gt;// how to clear and hide the text box when this option is  
    selected?
  &lt;option value="somevalue"&gt;somename&lt;/option&gt;// when this option is selected then it 
   displays an empty text box
  &lt;option value="somevalue1"&gt;somename1&lt;/option&gt;when this option is selected then it also 
   displays the same empty text box
  &lt;/select&gt;
  // in the following div, text box is being displayed
  &lt;div id="textbox"&gt;
  // here text box is displayed when option 2nd or 3rd is selected from the above combo
  &lt;/div&gt;
  </code></pre>
  
  <p>server side (combo.jsp)</p>
  
  <pre><code>JSONObject jsonObj= new JSONObject(); 
   jsonObj.put("isTrue","true");
  response.setContentType("application/json");
  response.getWriter().write(jsonObj.toString());
  </code></pre>