jQuery中$(function())的作用

$(function(){//五分钟无操作，返回系统首页,timeToreturn.js

    function timeToReturn(){

        window.location.href = "http://localhost:8080/zhongCourt/";

    }

    var nowtime = Date.parse(new Date());

    var timeend = Date.parse(new Date());

    $("body").click(function(){

        nowtime = Date.parse(new Date());

        console.log("nowtime" + nowtime);  

    });

    function check(){

        timeend = Date.parse(new Date());

        console.log("check");

        if((timeend - nowtime) > 300000){

            timeToReturn();

        }

        setTimeout(check,10000);

    }

    setTimeout(check,10000);

})