title: PHP header xls using .xlsx
body: <p>I Use this code for exporting excel</p>
  <pre><code>&lt;?php
   header(&quot;Content-type: application/vnd-ms-excel&quot;);
   header(&quot;Content-Disposition: attachment; filename=$title.xls&quot;);
   header(&quot;Pragma: no-cache&quot;);
   header(&quot;Expires: 0&quot;);
   ?&gt;
  </code></pre>
  <p>But i can't change $title.xls to .xlsx format</p>
  <p>Please give me solution</p>