title: PHP Event Handlers
body: <p>.net developer trying to do a php site for a friend, so far everything is going great but I was wondering if php has something like a textchanged event.  Here is what I want to do, I want a drop down box to be appended with data retrieved from a database based on what the user enters in a textbox above(Using the text in the textbox as a parameter to retrieve data from a database and append it to the drop down without reloading the entire page.)</p>
  
  <pre><code>  protected void TextBox1_TextChanged(object sender, EventArgs e)
      {
          //Do stuff
      }
  </code></pre>
  
  <p>The block off code above is in asp.net but i want to implement something similar in php.</p>