<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<style>
#div1{width:100px;height:100px;background:red;}
</style>
<script type="text/javascript">
function setColor(color)
{
var oDiv=document.getElementById("div1");
oDiv.style.background=color;
}
</script>
</head>
<body>
<input type="button" value="变红" onclick="setColor('red')"/>
<input type="button" value="变黄" onclick="setColor('yellow')"/>
<input type="button" value="变黑" onclick="setColor('black')"/>
<div id="div1"></div>
</body>
</html>
来源：https://www.cnblogs.com/ll-taj/p/5173392.html