ajaxdemo

function RequestAjax(){
    // this.init(str);
  };

  RequestAjax.prototype.init = function(str){
    var xhr = this.createXHR();
    // console.log(encodeURIComponent(str));
    
    xhr.onreadystatechange = function(){
      if(xhr.readyState == 4){
        if(xhr.status == 200){
          var data = xhr.response;
          console.log(data);
        }
      }
    };

    xhr.open("GET", "../demo.php?q="+str, true);


    xhr.send(null);


  };

  RequestAjax.prototype.createXHR = function(){
    if(typeof XMLHttpRequest != "undefind"){
      return new XMLHttpRequest();    
    }else if(typeof ActiveXObject != "undefind"){
      if(typeof arguments.callee.activeXString != "string"){
        var versions = ["MSXML2.XMLHttp.6.0","MSXML2.XMLHttp.3.0","MSXML2.XMLHttp"],
        len = versions.length;
        for(var i = 0; i < len; i ++){
          try{
            new ActiveXObject(versions[i]);
            arguments.callee.activeXString = versions[i];
            break;
          }catch(e){
            console.log(e);
          }
        }
      }

      return new ActiveXObject(arguments.callee.activeXString);
      
    }else{
      throw new Errow("NO XHR object");
    }
  };