Juqery 定时器 settimeout setInterval

setTimeout 只执行一次

    setTimeout(loading_tree,2000);
    
    function loading_tree(){

         $('body').mLoading("hide");
         $('#btn3').show();
     }

setIntervalt 每隔几秒执行一次

    setInterval(loading_tree1,2000);

    function loading_tree1(){

       console.log(32);
     }