var imgs=document.querySelectorAll("img");  //获取所有图片
var num=0;
imgs.forEach(function(i,index){   //遍历图片
    var img = new Image();
    var load=document.querySelector(".loading");

    img.onload = function(){    //显示图片加载百分比
        num++;
        var hone=document.querySelector("h1");
        hone.innerHTML=parseInt(num/imgs.length*100)+"%";

        if(num>=index){     //隐藏遮罩层
            load.style.display="none"
        }
    }

    var elemt=i.getAttribute("src");
    img.src = elemt;
})