title: PHP interaction with AJAX
body: <p>So I have this function in my javascript file:</p>
  
  <pre><code>function UpdateThisCourseHistory(){
      var ajax= new Ajax.Request("runNeededQueries.php",
              {
                  method: "POST",
                  parameters: {database: "history", action:"update"},
                  onSuccess: function(){alert("This Course History Entry Has Been Updated");},
                  onFailure: function(){alert("Could Not Find The Entry With The Specified Primary Key");}        
              }
      );
  }
  </code></pre>
  
  <p>Suppose this is my php file</p>
  
  <pre><code>&lt;?php
  header('HTTP/1.0 400 Bad Request');
   ?&gt;
  </code></pre>
  
  <p>Would this make the onFailure method execute?</p>