function loadXml(str) {if (str == null) {return null;}var doc = str;try{doc = createXMLDOM();doc.async = false;doc.loadXML(str);}catch(e){doc = $.parseXML(str);}return doc;
}

/**
*xml对象转json对象
*xmlObj:xml对象
*nodename:节点路径('ROOT/ITEM')
*isarray:true,强制返回数组对象
**/
function xmltojson(xmlObj,nodename,isarray){var obj=$(xmlObj);var itemobj={};var nodenames="";var getAllAttrs=function(node){//递归解析xml 转换成json对象var _itemobj={};var notNull=false;var nodechilds=node.childNodes;var childlenght=nodechilds.length;var _attrs=node.attributes;var firstnodeName="#text";try{firstnodeName=nodechilds[0].nodeName;}catch(e){}if((childlenght>0&&firstnodeName!="#text")||_attrs.length>0){var _childs=nodechilds;var _childslength=nodechilds.length;var _fileName_="";if(undefined!=_attrs){var _attrslength=_attrs.length;for(var i=0; i<_attrslength; i++){//解析xml节点属性var attrname=_attrs[i].nodeName;var attrvalue=_attrs[i].nodeValue;_itemobj[attrname]=attrvalue;}}for (var j = 0; j < _childslength; j++) {//解析xml子节点var _node = _childs[j];var _fildName = _node.nodeName;if("#text"==_fildName){break;};if(_itemobj[_fildName]!=undefined){//如果有重复的节点需要转为数组格式if(!(_itemobj[_fildName] instanceof Array)){var a=_itemobj[_fildName];_itemobj[_fildName]=[a];//如果该节点出现大于一个的情况 把第一个的值存放到数组中
            }}var _fildValue=getAllAttrs(_node);try{_itemobj[_fildName].push(_fildValue);}catch(e){_itemobj[_fildName]=_fildValue;_itemobj["length"]=1;}}}else{_itemobj=(node.textContent==undefined)?node.text:node.textContent;}return _itemobj;};if(nodename){nodenames=nodename.split("/")}for(var i=0;i<nodenames.length;i++){obj=obj.find(nodenames[i]);}$(obj).each(function(key,item){if(itemobj[item.nodeName]!=undefined){if(!(itemobj[item.nodeName] instanceof Array)){var a=itemobj[item.nodeName];itemobj[item.nodeName]=[a];}itemobj[item.nodeName].push(getAllAttrs(item));}else{if(nodenames.length>0){itemobj[item.nodeName]=getAllAttrs(item);}else{itemobj[item.firstChild.nodeName]=getAllAttrs(item.firstChild);}}});if(nodenames.length>1){itemobj=itemobj[nodenames[nodenames.length-1]];}if(isarray&&!(itemobj instanceof Array)&&itemobj!=undefined){itemobj=[itemobj];}return itemobj;
};

var xmlstr="<USERS>" +"<USER state='0'>" +"<USERNAME type='String'>张三</USERNAME>" +"<USERID type='String'>00001</USERID>" +"</USER>" +"<USER state='1'>" +"<USERNAME type='String' size='100'>李四</USERNAME>" +"<USERID>00002</USERID>" +"</USER>" +"<USER>" +"<USERNAME>李四</USERNAME>" +"<USERID>00002</USERID>" +"</USER>" +"</USERS>";
var xmlobj=loadXml(xmlstr);

{"USERS": {"USER": [{"state": "0","USERNAME": {"type": "String"},"length": 1,"USERID": {"type": "String"}},{"state": "1","USERNAME": {"type": "String","size": "100"},"length": 1,"USERID": "00002"},{"USERNAME": "李四","length": 1,"USERID": "00002"}],"length": 1}
}

[{"state": "0","USERNAME": {"type": "String"},"length": 1,"USERID": {"type": "String"}},{"state": "1","USERNAME": {"type": "String","size": "100"},"length": 1,"USERID": "00002"},{"USERNAME": "李四","length": 1,"USERID": "00002"}
]

PS：这里再为大家提供几款关于xml操作的在线工具供大家参考使用：

在线XML/JSON互相转换工具：
http://tools.jb51.net/code/xmljson

在线格式化XML/在线压缩XML：
http://tools.jb51.net/code/xmlformat

XML在线压缩/格式化工具：
http://tools.jb51.net/code/xml_format_compress

XML代码在线格式化美化工具：
http://tools.jb51.net/code/xmlcodeformat