/*  
power by dcboy  
method:cross domain to get JSON  
example:  
 
var proxy=new ScriptTagProxy();  
proxy.loadUrl('http://kending.fullon-hotels.com.cn/gate/gb/search.yahooapis.com/ImageSearchService/V1/imageSearch?', 'appid=YahooDemo&query=Madonna&output=json', window,process);  
function process(a){  
  alert('Server return:'+a)  
}  
return a is [Object object]  
*/  
var ScriptTagProxys={TRANS_ID:1000};
ScriptTagProxy=function(){}
ScriptTagProxy.prototype={
    initialize:function(){this.head = document.getElementsByTagName("head")[0];},
    loadUrl : function(url, params, caller,onComplete, onFailure){
       transId=++ScriptTagProxys.TRANS_ID;
       var trans ={
          id : transId,
          cb : "stcCallback"+transId,
          scriptId : "stcScript"+transId,
          url : url,
          params : params,
          caller : caller,
          onComplete : onComplete,
          onFailure :onFailure
       };
       var conn = this;
       window[trans.cb] = function(o){conn.handleResponse(o, trans);}
        params='callback='+trans.cb+'&'+params;
        var script = document.createElement("script");
        script.setAttribute("src", url+params);
        script.setAttribute("type", "text/javascript");
        script.setAttribute("id", trans.scriptId);
        //trans.timeoutId=setTimeout(this.handleFailure.bind(conn,trans), 20000);
		//trans.timeoutId=setTimeout(this.handleFailure(trans), 20000);
        this.head.appendChild(script);
  },
  handleResponse : function(o, trans){
    this.destroyTrans(trans, true);
    trans.onComplete.call(trans.caller||window, o);
  },
  handleFailure : function(trans){
    this.destroyTrans(trans, false);
    if(trans.onFailure){ trans.onFailure.call(trans.caller||window, null);
    }else{alert('Load Timeout');}
  },
  destroyTrans : function(trans, isLoaded){
    this.head.removeChild(document.getElementById(trans.scriptId));
    clearTimeout(trans.timeoutId);
    if(isLoaded){window[trans.cb] = undefined;
      try{delete window[trans.cb];}catch(e){}
    }else{
      window[trans.cb] = function(){window[trans.cb] = undefined;
      try{delete window[trans.cb];}catch(e){}
      };    
    }   
  }   
}