如下代码,为什么在创建XMLHttpRequest时是一串文本而不是一个对象,要使用AJAX需要配置什么文件吗?<script language="javascript" type="text/javascript">
var xmlHttp ;
var flag_userid = false ;
function createXMLHttp(){
if(window.XMLHttpRequest){
xmlHttp = new XMLHttpRequest() ;
} else {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP") ;
}
}
function ajaxCheckUserid(username){
createXMLHttp() ;
xmlHttp.open("POST","~/User/Validate.aspx?UserName"+username) ;
xmlHttp.onreadystatechange = checkUseridCallback ;
xmlHttp.send(null) ;
document.getElementById("userid_msg").innerHTML = "正在验证..." ;
}
function checkUseridCallback(){
if(xmlHttp.readyState == 4){
if(xmlHttp.status == 200){
var text = xmlHttp.responseText ;
//alert(text);
if(text == "true"){ // 用户id已经存在了
flag_userid = false ;
document.getElementById("userid_msg").innerHTML="<font size='-1' color='#FF0000'>此用户ID已经存在,请重新输入</font>";
}else{
flag_userid=true;
document.getElementById("userid_msg").innerHTML="<img src='../images/yes_point.gif'/>";
}
}
}
}
</script>
var xmlHttp ;
var flag_userid = false ;
function createXMLHttp(){
if(window.XMLHttpRequest){
xmlHttp = new XMLHttpRequest() ;
} else {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP") ;
}
}
function ajaxCheckUserid(username){
createXMLHttp() ;
xmlHttp.open("POST","~/User/Validate.aspx?UserName"+username) ;
xmlHttp.onreadystatechange = checkUseridCallback ;
xmlHttp.send(null) ;
document.getElementById("userid_msg").innerHTML = "正在验证..." ;
}
function checkUseridCallback(){
if(xmlHttp.readyState == 4){
if(xmlHttp.status == 200){
var text = xmlHttp.responseText ;
//alert(text);
if(text == "true"){ // 用户id已经存在了
flag_userid = false ;
document.getElementById("userid_msg").innerHTML="<font size='-1' color='#FF0000'>此用户ID已经存在,请重新输入</font>";
}else{
flag_userid=true;
document.getElementById("userid_msg").innerHTML="<img src='../images/yes_point.gif'/>";
}
}
}
}
</script>
不错的
var request = false;
if(window.XMLHttpRequest) {
request = new XMLHttpRequest();
if(request.overrideMimeType) {
request.overrideMimeType('text/xml');
}
} else if(window.ActiveXObject) {
var versions = ['Microsoft.XMLHTTP', 'MSXML.XMLHTTP', 'Microsoft.XMLHTTP', 'Msxml2.XMLHTTP.7.0', 'Msxml2.XMLHTTP.6.0', 'Msxml2.XMLHTTP.5.0', 'Msxml2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP'];
for(var i=0; i<versions.length; i++) {
try {
request = new ActiveXObject(versions[i]);
if(request) {
return request;
}
} catch(e) {
//alert(e.message);
}
}
}
return request;