点击更换背景图片

<style>
    * {
        margin: 0px;
        padding: 0px;
    }
    body {
        background-image: url("images/1.jpg");
    }
    #mask {
        background-color: rgba(255, 255, 255, 0.3);
        height: 200px;
        text-align: center;
    }
    #mask img {
        width: 200px;
        margin-top: 35px;
        cursor: pointer;
    }

</style>

 var div=myD("mask");
 var body=myD("bd");
 var nodes=div.children;
 for(var i=0;i<nodes.length;i++){
     nodes[i].onclick=function () {
         console.log("aas");
         body.style.backgroundImage="url("+this.src+")";
     }
 }