Ajax获取json信息例子

<script src="../Scripts/jquery-1.4.1.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(function () {
$("#BtnAjax").click(function () {
var xhr;
if (XMLHttpRequest) {
xhr = new XMLHttpRequest(); //ie8,ie9
}
else {
xhr = new ActiveXObject("XMLHttpRequest?IP=33"); //ie6
}
//get请求
//                xhr.open("GET", "ProcessAjax.ashx", "True");
//                xhr.send();

//post请求
xhr.open("Post", "ProcessAjax.ashx", true);

xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xhr.send("IP=33");
xhr.onreadystatechange = function () {
if (xhr.readyState == 4) {
alert(xhr.responseText);
}
}
});
});
</script>