title: php file specified in the ajax parameter of datatables js is not executing
body: <p>I am trying to populate a table from the DataTables js library. The data is extracted by the php script which I pass as the ajax parameter, just like the example on the datatables site specifies.</p>
  
  <p>However, I get the error that the response is not valid json. Looking at my dev tools, I can see that it is not! In fact, the response is simply the complete contents of the php script which is suppose to run and return some data.</p>
  
  <p>So, the DataTables function is seeing the ajax parameter as a source of the data (and thus tries to interpret it as json) and not a script to run, which will return the data.</p>
  
  <p>What am I doing wrong?</p>
  
  <p>Here is the javascript which calls the php:</p>
  
  <pre><code>$("#dataBilling").DataTable({
   "processing":true,
    "serverSide": true,
    "ajax":"scripts/readfromdb.php"
  });
  </code></pre>
  
  <p>The contents of readfromdb.php is not relevant, since no matter what it is, it is not even being executed. Like I said, devtools shows the XHR response as the entire contents of that php file.</p>