点击图片body就变成图片
修改元素属性 src
1.获取元素
var one = document.getElementById("one");
var tu = document.getElementById("tu");
var img = document.querySelector("img");
one.onclick = function () {
img.src = "/img/images/1.jpg";
img.title = "第一张";
};
tu.onclick = function () {
img.src = "/img/images/3.jpg";
img.title = "第二张";
};