title: How to generate an Excel document with multiple worksheets from PHP?
body: <p>I want to generate an MS Excel file from PHP. I know one can do something like this:</p>
  
  <pre><code>header ( "Content-type: application/vnd.ms-excel" );
  header ( "Content-Disposition: attachment; filename=foo_bar.xls" );
  </code></pre>
  
  <p>But it will generate a file with just one Sheet. What I want is generating a file with multiple sheets. How can I do that? Maybe there's a third party library, but I haven't found too much.</p>