我对ajax的理解： 在web客户端，XMLHttpRequest和服务器交换数据（get,post),通过ResponseText或者ResponseXML获取数据后，将数据转交XMLDOM对象处理，最终交由HTMLDOM对象输出到页面上。 所以，要精通ajax，其实是要精通三个对象:XMLHttpRequest,XMLDOM,HTMLDOM. 重所周知，ie和非ie下创建这两个对象的方法不同，为了统一创建方式，我将他们做了下简单封装。
/* /返回XMLHttpRequest对象 / */ function CreateXMLHttpRequest() { var req; _XMLHTTP = [ " Msxml2.XMLHTTP.6.0 " , " Msxml2.XMLHTTP.5.0 " , " Msxml2.XMLHTTP.4.0 " , " MSXML2.XMLHTTP.3.0 " , " MSXML2.XMLHTTP " , " Microsoft.XMLHTTP " ]; _newActiveXObject = function (axarray) { var returnValue; for ( var i = 0 ; i < axarray.length; i ++ ) { try {returnValue = new ActiveXObject(axarray[i]); break ; } catch (ex) {} } return returnValue; }; if (window.XMLHttpRequest) { req = new XMLHttpRequest(); } else if (window.ActiveXObject && ! (navigator.userAgent.indexOf( " Mac " ) >= 0 && navigator.userAgent.indexOf( " MSIE " ) >= 0 )) { req = _newActiveXObject(_XMLHTTP); } return req; } // End CreateXMLHttpRequest() // --------------------------------------------------------------------------------------------------------------------------// /* /返回XMLDOM对象 / */ function CreateXMLDOM() { var req; _DOMDocument = [ " Msxml2.DOMDocument.6.0 " , " Msxml2.DOMDocument.5.0 " , " Msxml2.DOMDocument.4.0 " , " Msxml2.DOMDocument.3.0 " , " MSXML2.DOMDocument " , " MSXML.DOMDocument " , " Microsoft.XMLDOM " ]; _newActiveXObject = function (axarray) { var returnValue; for ( var i = 0 ; i < axarray.length; i ++ ) { try {returnValue = new ActiveXObject(axarray[i]); break ; } catch (ex) {} } return returnValue; }; if (window.XMLHttpRequest) { req = document.implementation.createDocument( "" , "" , null ); } else if (window.ActiveXObject && ! (navigator.userAgent.indexOf( " Mac " ) >= 0 && navigator.userAgent.indexOf( " MSIE " ) >= 0 )) { req = _newActiveXObject(_DOMDocument); } return req; } // End CreateXMLDOM() 查看更多内容: js中国 下载代码使用说明:javascript库说明 引用:<script type="text/javascript" src="XMLHttpRequest.js"></script>
1,创建XMLHttpRqruest对象 var XMLHttp = CreateXMLHttpRequest();
2,创建XMLDOM对象 var XMLDOM = CreateXMLDOM();
转载于:https://www.cnblogs.com/wangxiang/articles/995107.html
