PC监听鼠标和键盘事件，定时无响应退出

直接上代码：

window.onload = function () {
    initScreenSaver();
}

//0912 add
function ScreenSaver(settings){     

    this.settings = settings;     

    this.nTimeout = this.settings.timeout;     

    document.body.screenSaver = this;
    // link in to body events
    document.body.onmousemove = ScreenSaver.prototype.onevent;
    document.body.onmousedown = ScreenSaver.prototype.onevent;
    document.body.onkeydown = ScreenSaver.prototype.onevent;
    document.body.onkeypress = ScreenSaver.prototype.onevent;     

    var pThis = this;
    var f = function(){pThis.timeout();}
    this.timerID = window.setTimeout(f, this.nTimeout);
}
ScreenSaver.prototype.timeout = function(){
   if ( !this.saver ){
      window.history.back(-1)//无动作跳转地址
   }
}
ScreenSaver.prototype.signal = function(){
   if ( this.saver ){
      this.saver.stop();
   }     

   window.clearTimeout(this.timerID);     

   var pThis = this;
   var f = function(){pThis.timeout();}
   this.timerID = window.setTimeout(f, this.nTimeout);
}     

ScreenSaver.prototype.onevent = function(e){
   this.screenSaver.signal();
}     

var saver;
function initScreenSaver(){
   saver = new ScreenSaver({timeout:20000});   //无动作时间
}