function ajax(options) {  options = options || {};  options.type = (options.type || "GET").toUpperCase();  options.dataType = options.dataType || "json";  var params = formatParams(options.data);  //創(chuàng)建xhr對(duì)象 - 非IE6  if (window.XMLHttpRequest) {    var xhr = new XMLHttpRequest();  } else { //IE6及其以下版本瀏覽器    var xhr = new ActiveXObject('Microsoft.XMLHTTP');  }  //GET POST 兩種請(qǐng)求方式  if (options.type == "GET") {    xhr.open("GET", options.url + "?" + params, true);    xhr.send(null);  } else if (options.type == "POST") {    xhr.open("POST", options.url, true);    //設(shè)置表單提交時(shí)的內(nèi)容類型    xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");    xhr.send(params);  }  //接收  xhr.onreadystatechange = function () {    if (xhr.readyState == 4) {      var status = xhr.status;      if (status >= 200 && status < 300) {        options.success && options.success(xhr.responseText);      } else {        options.fail && options.fail(status);      }    }  }}//格式化參數(shù)function formatParams(data) {  var arr = [];  for (var name in data) {    arr.push(encodeURIComponent(name) + "=" + encodeURIComponent(data[name]));  }  arr.push(("v=" + Math.random()).replace(".",""));  return arr.join("&");}

ajax({  url: "data.json",  type: "GET",  data: {},  dataType: "json",  success: function (response) {    // 此處放成功后執(zhí)行的代碼     // 解析返回的字符串 轉(zhuǎn)為json對(duì)象    var usingdata = eval("("+response+")").data;  }  fail: function (status) {    // 此處放失敗后執(zhí)行的代碼  }});