三种方式获取XMLHttpRequest对象

  获取XmlHttpRequest对象

  

复制代码 代码如下:

  //1

  function getXMLHttpRequest() {

  var xmlHttpReq;

  try { // Firefox, Opera 8.0+, Safari

  xmlHttpReq = new XMLHttpRequest();

  } catch (e) {

  try {// Internet Explorer

  xmlHttpReq = new ActiveXObject("Msxml2.XMLHTTP");

  } catch (e) {

  try {

  xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");

  } catch (e) {

  }

  }

  }

  return xmlHttpReq;

  }

  //2

  function getXMLHttpRequest() {

  var xmlHttpReq = null;

  if (window.ActiveXObject) {// Internet Explorer

  xmlHttpReq = new ActiveXObject("MSXML2.XMLHTTP.3.0");

  } else if (window.XMLHttpRequest) {

  xmlHttpReq = new XMLHttpRequest();

  }

  return xmlHttpReq;

  }

  //3

  function getXMLHttpRequest() {

  var xmlHttpReq = null;

  if (window.XMLHttpRequest) {// Mozilla Firefox, Opera 8.0+, Safari

  xmlHttpReq = new XMLHttpRequest();

  } else {

  if (window.ActiveXObject) {// Internet Explorer

  try {

  xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");

  } catch (e) {

  try {// Internet Explorer

  xmlHttpReq = new ActiveXObject("Msxml2.XMLHTTP");

  } catch (e) {

  }

  }

  }

  }

  return xmlHttpReq;

  }