ajax交互

原始版的ajax

function $(id) {
		return document.getElementById(id);
	}
	//
	function getXMLHttpRequest() {
		var xmlhttpp = null;
		if (window.XMLHttpRequest) {
			xmlhttp = new XMLHttpRequest();
		} else {
			xmlhttp = new ActiveXObject("Microsoft.XMLHttp");//IE56
		}
		return xmlhttp;
	}
	//
	function doLogin() {
		var username = $("username").value;
		console.log(username);
		var password = $("password").value;
		console.log(password);
		var xmlHR = getXMLHttpRequest();
		xmlHR.onreadystatechange = function() {
			if (xmlHR.readyState == 4 && xmlHR.status == 200) {
				var respWord = xmlHR.responseText;
				console.log(respWord);
				$("span1").innerHTML = "";
				$("span2").innerHTML = "";
				var resultJson=JSON.parse(respWord);
				if ("1"==resultJson.state) {
					$("span2").innerHTML = resultJson.message;
					window
							.setTimeout(
									function() {
										window.location.href = "hello.jsp"
									}, 1000)
				} else if ("-1"==resultJson.state) {
					$("span1").innerHTML = resultJson.message;
				} else if("-2"==resultJson.state){
					$("span2").innerHTML = resultJson.message;
				}
			}
		}
		var url = "query.do";
		xmlHR.open("POST", encodeURI(url), true);
		xmlHR.setRequestHeader("Content-type",
				"application/x-www-form-urlencoded");
		xmlHR.send("username=" + username + "&password=" + password);
		//发送请求
		xmlhttp.open("GET", url, true);
		xmlhttp.send();
	}

$.ajax({
	"url" : url,
	"data" : "id=" + id,
	"type" : "GET",
	"dataType" : "json",
	"success" : function(obj) {
								console.log(obj.message);
								showAddressList();
	},
	error:function(){}
});

@RequestMapping("/get_area_list.do")
	@ResponseBody
	public ResponseResult getAreaList(String cityCode) {
		System.out.println(cityCode);
		rr.setState(ResponseResult.STATE_OK);
		rr.setMessage("成功");
		rr.setData(service.findAreaByCityCode(cityCode));
		return rr;
	}

var data = $('#login-form').serialize();