main.htm 
----------------------------------------------------------------------------- 
<script> 
function getArray(){ 
   var xmlhttp = new ActiveXObject ("Microsoft.XMLHTTP"); 
   xmlhttp.Open("GET","a.php?name="+escape(event.srcElement.value),false); 
   xmlhttp.Send(); 
   document.all.p.innerHTML=unescape(xmlhttp.responseText); 
} 
</script> 

<input type="text" onKeyUp="getArray()"> 
<div id="p"></div> 

a.php 
--------------------------------------------------------------- 
<?php 
if(isset($_GET["name"])){ 
   preg_match_all("'.'",$_GET["name"],$arr); 
   print_r($arr[0]); 
} 
?>