/*
1. 变量
2. 事件
3. 函数
4. 属性
*/
目前，关于事件我们只学了一个点击事件。
如果觉得前边获取元素时写的document.getElement(s)..太长了，那么可以通过声明变量来简化它
例如：
<script>
var box = document.getElementById(‘ box ‘)
var btn = document.getElementById(‘ btn ‘)
btn.onclick = function(){
box.style.background=" red "
}
</script>
可以看到利用js可以通过点击其他位置控制另一个元素样式的变化
利用这一点，我们做了一个小东西，以下是代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<link rel="stylesheet" href="../css/index.css" />
</head>
<body>
<div id="main">
<div id="word">
<span>请为下边的DIV设置样式:</span>
<button id="set">点击设置</button>
</div>
<div id="box"></div>
</div>
<div id="bg">
<div id="center">
<div id="color">
<span>请选择背景色：</span>
<button id="red">红</button>
<button id="yel">黄</button>
<button id="blue">蓝</button>
</div>
<div id="width">
<span>请选择宽度：</span>
<button id="w200">200</button>
<button id="w300">300</button>
<button id="w400">400</button>
</div>
<div id="height">
<span>请选择高度：</span>
<button id="h200">200</button>
<button id="h300">300</button>
<button id="h400">400</button>
</div>
<div id="choose">
<button id="reg">恢复</button>
<button id="sure">确定</button>
</div>
</div>
</div>
<script>
var set = document.getElementById (‘set‘);
var box = document.getElementById (‘box‘);
var bg = document.getElementById (‘bg‘);
var red = document.getElementById (‘red‘);
var yel = document.getElementById (‘yel‘);
var blue = document.getElementById (‘blue‘);
var w200 = document.getElementById (‘w200‘);
var w300 = document.getElementById (‘w300‘);
var w400 = document.getElementById (‘w400‘);
var h200 = document.getElementById (‘h200‘);
var h300 = document.getElementById (‘h300‘);
var h400 = document.getElementById (‘h400‘);
var reg = document.getElementById (‘reg‘);
var sure = document.getElementById (‘sure‘);
set.onclick = function(){
bg.style.display = ‘block‘;
}
red.onclick = function(){
box.style.background = ‘#f50b42‘;
}
yel.onclick = function(){
box.style.background = ‘#f9e74f‘;
}
blue.onclick = function(){
box.style.background = ‘#84a8f1‘;
}
w200.onclick = function(){
box.style.width = ‘200px‘;
}
w300.onclick = function(){
box.style.width = ‘300px‘;
}
w400.onclick = function(){
box.style.width = ‘400px‘;
}
h200.onclick = function(){
box.style.height = ‘200px‘;
}
h300.onclick = function(){
box.style.height = ‘300px‘;
}
h400.onclick = function(){
box.style.height = ‘400px‘;
}
reg.onclick = function(){
box.style.width = ‘142px‘;
box.style.height = ‘142px‘;
box.style.background = ‘#fff‘;
}
sure.onclick = function(){
bg.style.display = ‘none‘;
}
</script>
</body>
</html>
从这里，我初次感受到了 js 的灵活，好多东西还没见识到，要继续努力才是。
