title: How can I write data into an excel using PHP?
body: <p>Is it possible to append content to an .xls file using PHP <code>fwrite()</code>?</p>
  <p>When I try this using <code>fwrite()</code>, the resulting file causes an error message in Excel 2007.</p>
  <p>Is there a specific separator I can use to accomplish this?</p>
  <p>Is it possible without a third party library?</p>