<span style="font-size:12px;">ajax 验证
var xmlHttpRequest;
function createXMLHttpRequest(){
if (window.XMLHttpRequest){
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlHttpRequest = new XMLHttpRequest();
}else{
// code for IE6, IE5
xmlHttpRequest = new ActiveXObject("Microsoft.XMLHTTP");
}
}
function validate(obj){
var userId = obj.value;
if(userId.length != 0 ){
createXMLHttpRequest();
}
xmlHttpRequest.onreadystatechange=callBack;
var url = "XXX" + "&date=" + new Date().getTime();
xmlHttpRequest.open("GET",url,true);
xmlHttpRequest.send(null);
}
function callBack(){
//alert(xmlHttpRequest.readyState);
if (xmlHttpRequest.readyState==4){
if(xmlHttpRequest.status==200){
//alert(xmlHttpRequest.responseText);
}else{
alert("响应未完成!!!");
}
}else{
//alert("请求未完成");
}
}</span>