XMLHttpRequest of ajax

【编者按】：网学网Ajax为您提供XMLHttpRequest of ajax参考，解决您在XMLHttpRequest of ajax学习中工作中的难题，参考学习。

调用 function(Url) {
  var XML = new XMLHttpRequest();
  XML.onreadystatechange = function() {
    if (XML.readyState == 4)
    {
      if (XML.status == 200)
      {
        //XML.responseText
      }
      else
      {
        //XML.statusText
      }
    }
    else
    {
      //数据加载中...
    }
  };
  XML.open("GET",Url);
  XML.send(null);
};定义XMLHttpRequest 适应不同的浏览器 // IE support
if (window.ActiveXObject && !window.XMLHttpRequest)
{
  window.XMLHttpRequest = function()
    {
      var msxmls = new Array(''Msxml2.XMLHTTP.5.0'',''Msxml2.XMLHTTP.4.0'',''Msxml2.XMLHTTP.3.0'',''Msxml2.XMLHTTP'',''Microsoft.XMLHTTP'');
      for (var i = 0; i < msxmls.length; i++)
      {
        try
        {
          return new ActiveXObject(msxmls[i]);
        }
        catch (e)
        {
        }
      }
      return null;
    };
}

// Opera support
if (window.opera && !window.XMLHttpRequest)
{
  window.XMLHttpRequest = function()
  {
    this.readyState = 0; // 0=uninitialized,1=loading,2=loaded,3=interactive,4=complete
    this.status = 0; // HTTP status codes
    this.statusText = '''';
    this._headers = [];
    this._aborted = false;
    this._async = true;
    this._defaultCharset = ''ISO-8859-1'';
    this._getCharset = function()
    {
      var charset = _defaultCharset;
      var contentType = this.getResponseHeader(''Content-type'').toUpperCase();
      val = contentType.indexOf(''CHARSET='');
      if (val != -1)
      {
        charset = contentType.substring(val);
      }
      val = charset.indexOf('';'');
      if (val != -1)
      {
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