前端之家收集整理的这篇文章主要介绍了
ajax判断用户名是否存在，
前端之家小编觉得挺不错的，现在分享给大家，也给大家做个参考。
$(function (){
$("#txtEmail").blur(function(){
var xhr;
if(window.ActiveXObject){
xhr=new ActiveXObject("Microsoft.XMLHTTP");
}else{
xhr=new XMLHttpRequest();
}
xhr.open("post","${pageContext.request.contextPath}/user/user_checkEmail");
xhr.setRequestHeader("content-type","application/x-www-form-urlencoded");
xhr.send("u.email="+$("#txtEmail").val());
//滚动进度条出现
$("#sig").attr("src","${pageContext.request.contextPath}/registerImg/load.gif").show();
xhr.onreadystatechange=function(){
if(xhr.readyState==4&&xhr.status==200){
var ret=xhr.responseText;
if("ok"==ret){
//对勾显示
$("#sig").attr("src","${pageContext.request.contextPath}/registerImg/ok.gif");
}else{
$("#sig").attr("src","${pageContext.request.contextPath}/registerImg/error.jpg");
}
}
};
});
<tr>
<td valign="top" class="w1">请填写您的Email地址：</td>
<td><input name="u.email" type="text" id="txtEmail"
class="text_input" />
<img id="sig" height="24px" width="24px" style="display:none;margin-left:15px;padding:0 0 3px 0;vertical-align: bottom;"/>
<div class="text_left" id="emailValidMsg">
<p>请填写有效的Email地址，在下一步中您将用此邮箱接收验证邮件。</p>
<span id="info" style="color:red"></span>
</div>
</td>
</tr>
原文链接：https://www.f2er.com/ajax/161168.html
