Ajax和便携式OS

Well, i have an select list in my php page and i want to refresh only that with new data from my database.Idone it using ajax but on android or other mobiles OSes this messes up the layout.Is there a problem with protable OSes and ajax?Can you give me any hints to solve this problem?

Edited

/*function loadXMLDoc()
{
var xmlhttp;
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
  xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
      var sel1 = document.getElementById("select1");
      var selectedI = sel1.selectedIndex;

      var i=0;
      var excode = excur[selectedI];
      var val = sel1.options[selectedI];

      excursioncode=excode;
      excindex = selectedI;
      val.innerHTML = xmlhttp.responseText;
      //alert(xmlhttp.responseText);

      //setTimeout("loadXMLDoc();",10000);
    }
  }

xmlhttp.open("POST","<?php echo SITE_ROOT;?>ajaxphp/ajax_get_seats.php?excode="+excursioncode+"&date="+selected_date,true);
xmlhttp.send();
}

function timedRefresh(timeoutPeriod) {
    tm=setTimeout("loadXMLDoc();",timeoutPeriod);
}
*/

This is some code that is doing the job.On a regular pc is working but on a mobile browser brings up problems.Anyu ideas

If the problem were with the AJAX, it would not be causing layout issues. Instead the problem is most likely with your implementation of using the data retrieved by AJAX. However, I can't provide any more insights because I have no clue what you're working on and have never experienced such a problem.