js中activeXString是什么

Question

在代码：function createXHR(){  if(typeof XMLHttpRequest !="undefined"){  return new XMLHttpRequest(); }else if(typeof ActiveXObject !="undefined"){   if(typeof arguments.callee.activeXString !="string"){   var versions = ["MSXML2.XMLHttp.6.0","MSXML2.XMLHttp.3.0","MSXML2.XMLHttp"];   var i,len;   for (i=0,len=versions.length;i<len;i++){   try{   new ActiveXObject(versions[i]);    arguments.callee.activeXString = versions[i];    break;}catch(ex){}}}return new ActiveXObject(arguments.callee.activeXString);}else{throw new Error("No XHR object available");}}在上述代码中activeXString是什么呢

Answer 1

function Foo() {

// do something;// arguments.callee.activeXString === 'foo';

};
Foo.activeXString = 'foo';