Lagging behind the first php+mysql province, city, prefecture level 3 linkage non-refresh menu source code using ajax technology_PHP tutorial

//var ab = new Array();  
var xmlHttp;  
var xmlHttpa; 
function createXMLHttpRequest() {  
    if (window.ActiveXObject) {  
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");  
    }   
    else if (window.XMLHttpRequest) {  
        xmlHttp = new XMLHttpRequest();  
    }  
}  
function createXMLHttpRequesta() {  
    if (window.ActiveXObject) {  
        xmlHttpa = new ActiveXObject("Microsoft.XMLHTTP");  
    }   
    else if (window.XMLHttpRequest) {  
        xmlHttpa = new XMLHttpRequest();  
    }  
}   

function startRequest() {  
    createXMLHttpRequest();  
    createXMLHttpRequesta();  
    xmlHttp.onreadystatechange = handleStateChange;  
    xmlHttpa.onreadystatechange = handleStateChangearea;  
    document.getElementById('select2').options.length = 0;  
    document.getElementById('select3').options.length = 0; 
    var url = document.form1.select1.value;  
    var qurl = "/regions.php?province="+url+"&time="+new Date().getTime();  
    xmlHttp.open("GET", qurl, true);  
    xmlHttp.send(null);  
    //setTimeout("startRequest()",2000);  
}  

function handleStateChange() {  
    if(xmlHttp.readyState == 4) {  
        if(xmlHttp.status == 200) {  
         var obj = document.getElementById('select2'); //将服务器返回的字符串写到页面中ID为select2的区域     
            obja = document.getElementById('select3'); //将服务器返回的字符串写到页面中ID为select3的区域    
            eval(xmlHttp.responseText);    

        }  
    }  
}  
function handleStateChangearea() {          
            eval(xmlHttpa.responseText);           
}  
//var ab = new Array();  

function startRequesta() {  
    createXMLHttpRequesta();  
    xmlHttpa.onreadystatechange = handleStateChangea;  
    document.getElementById('select3').options.length = 0;  
    var url = document.form1.select2.value;  
    var qurl = "/regions.php?city="+url+"&time="+new Date().getTime();  
    xmlHttpa.open("GET", qurl, true);  
    xmlHttpa.send(null);  
    //setTimeout("startRequest()",2000);  
}

function handleStateChangea() {
if(xmlHttpa.readyState == 4) {
if(xmlHttpa.status == 200) {
var obja = document.getElementBy Id('select3' );
eval(xmlHttpa.responseText);
//Write the string returned by the server to the area with the ID select3 on the page

} 🎜>
Data Island regions.php page code

$area = $area ? $area : "";
if($province && $city==''){
global $db; $i = 1;

$result = $db->query("SELECT DISTINCT city FROM ".TABLE_CITY." WHERE province=' $province' ORDER BY cityid");
while($r = $db->fetch_array($result))
{
$r[city]=iconv('gb2312','UTF- 8',$r[city]);
echo "obj.options[obj.options.length] = new Option('".$r[city]."','".$r[city]. "');n";
$i++;
}
$resultarea = $db->query("SELECT DISTINCT city FROM ".TABLE_CITY." WHERE province='$province' ORDER BY cityid ");
$r = $db->fetch_array($resultarea);
$city = $r[city];
$resulta = $db->query("SELECT DISTINCT area FROM ".TABLE_CITY." WHERE city='$city' ORDER BY cityid");
while($ra = $db->fetch_array($resulta))
{
$ra[area]= iconv('gb2312','UTF-8',$ra[area]);
echo "obja.options[obja.options.length] = new Option('".$ra[area]."', '".$ra[area]."');n";
$i++;
}


}
if($city && $province=='' ){
global $db; $i = 1;

$result = $db->query("SELECT DISTINCT area FROM ".TABLE_CITY." WHERE city='$city' ORDER BY cityid ");
while($r = $db->fetch_array($result))
{
$r[area]=iconv('gb2312','UTF-8',$r[ area]);
echo "obja.options[obja.options.length] = new Option('".$r[area]."','".$r[area]."');n" ;
$i++;
}
}
?> No changes have been made

This program can be used directly in phpcms3.0. If used elsewhere, please modify it yourself