<script type="text/javascript">
window.onload = function(){
var oBtn = document.getElementById('btn');
var oInp = document.getElementsByTagName('input')[0];
var oBox = document.getElementById('box');
oBtn.onclick = function(){
// 发ajax请求
// 1.创建XMLHttpRequest对象
var req = new XMLHttpRequest();
// 2.打开服务器连接 method url
req.open('get','${pageContext.request.contextPath}/reg_2?uname='+oInp.value,true);
// 3.发送请求
req.send();
// 4.调用回调函数获取响应信息
req.onload = function(){
if(req.responseText == 1){
oBox.innerHTML = '用户名已经注册';
oBox.style.color = 'red';
}else if(req.responseText == 0){
oBox.innerHTML = '用户名可以注册';
oBox.style.color = 'green';
}
}
}
}
</script>
