title: Do action when item selected
body: <p>I need to make some actions depending on which item from my dropdown box is selected.</p>
  
  <p>So I need to make it if an item with prefix Blue is selected then show one textbox below, and if any other item is selected then show some other stuff, how could I do that the easiest way?</p>
  
  <p>More explaination:
  Ok...I have a dropdown menu which contains a list of items. What I need to make is so that after they select an item with prefix Blue a input field under dropdown menu shows. If they select any other item something else will happen.</p>
  
  <p>What I have so far is my dropdown menu:</p>
  
  <pre><code>&lt;select id="select1" name="selectz1"&gt;
  &lt;?php
  $id = 0;
  while ($row = mysql_fetch_row($result)) {
      echo "&lt;option value=$id&gt;$row[0]&lt;/option&gt;";
      $id++;
  }
  ?&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>And that is what HTML generates:</p>
  
  <pre><code>&lt;form action="ThisPage.php" method="POST"&gt;
  Accounts: &lt;br /&gt;
  &lt;select id="select1" name="selectz1"&gt;
  &lt;option value=0&gt;account 2000-01&lt;/option&gt;&lt;option value=1&gt;account 2000-02&lt;/option&gt;
  &lt;option value=2&gt;blue 2000-03&lt;/option&gt;&lt;option value=3&gt;blue 2000-04&lt;/option&gt;
  &lt;/select&gt;
  &lt;/form&gt;
  </code></pre>