php的ajax简单实例

                var
                 xmlHttp


                function
                 showHint(str){
    
                if (str.length==0)
     { 
    document.getElementById("txtHint").innerHTML=""
    return
 }

    //获取xmlHttpObject对象，如果为空，提示浏览器不支持ajax
    xmlHttp=GetXmlHttpObject()

    if (xmlHttp==null){
        alert ("Browser does not support HTTP Request")
        return
     } 
     
     //获取urlvar url="gethint.php"
    url=url+"?q="+str
    url=url+"&sid="+Math.random()

     //回调函数，执行动作
    xmlHttp.onreadystatechange=stateChanged 

     //open
    xmlHttp.open("GET",url,true)
    xmlHttp.send(null)
} 

function stateChanged() { 
    if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete"){ 
        //将获取的信息插入到txtHint中
        document.getElementById("txtHint").innerHTML=xmlHttp.responseText 
    } 
}


//获取xml对象function GetXmlHttpObject(){
    var xmlHttp=null;
    try{
        // Firefox, Opera 8.0+, Safari
        xmlHttp=new XMLHttpRequest();
        }
    catch (e){
        // Internet Explorertry{
         xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
         }
        catch (e){
         xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
         }
    }
    return xmlHttp;
}

<?php
// Fill up array with names$a[]="Anna";
$a[]="Brittany";
$a[]="Cinderella";
$a[]="Diana";
$a[]="Eva";
$a[]="Fiona";
$a[]="Gunda";
$a[]="Hege";
$a[]="Inga";
$a[]="Johanna";
$a[]="Jiqing";
$a[]="Kitty";
$a[]="Linda";
$a[]="Nina";
$a[]="Ophelia";
$a[]="Petunia";
$a[]="Amanda";
$a[]="Raquel";
$a[]="Cindy";
$a[]="Doris";
$a[]="Eve";
$a[]="Evita";
$a[]="Sunniva";
$a[]="Tove";
$a[]="Unni";
$a[]="Violet";
$a[]="Liza";
$a[]="Elizabeth";
$a[]="Ellen";
$a[]="Wenche";
$a[]="Vicky";

//get the q parameter from URL$q=$_GET["q"];

//lookup all hints from array if length of q>0if (strlen($q) > 0)
{
$hint="";
for($i=0; $i<count($a); $i++)
 {
 if (strtolower($q)==strtolower(substr($a[$i],0,strlen($q))))
   {
   if ($hint=="")
     {
     $hint=$a[$i];
     }
   else
     {
     $hint=$hint." , ".$a[$i];
     }
   }
 }
}

//Set output to "no suggestion" if no hint were found
//or to the correct valuesif ($hint == "")
{
$response="no suggestion";
}
else
{
$response=$hint;
}

//output the responseecho$response;
?>