window.onload=function(){
                document.onkeydown=function(){
                    var e=window.event||arguments[0];
                        if(e.keyCode==123){
                            alert("哈哈哈");
                            return false;
                        }
                        else if((e.ctrlKey)&&(e.shiftKey)&&(e.keyCode==73)){
                        alert("哈哈哈");
                        return false;
                        }
                };
            }