<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<style>
.fontSize22
{
font-size:22px;
}
.fontWeight
{
font-weight:bold;
}
</style>
</head>
<body>
<div id="div1" class="fontSize22 fontWeight" style="color:red">div实例文本</div>
<button onclick="changeStyle()">changeStyle()</button>
<script>
function changeStyle()
{
var div1 = document.getElementById("div1");
//div1.className = "fontSize22";
//div1.className += " fontWeight";
//删除单个class=""样式
//div1.className = div1.className.replace(/fontSize22/,"");
//删除所有class=""样式
//div1.removeAttribute("class");
//删除style=""中的单个样式
div1.style.cssText = div1.style.cssText.replace(/red/,"blue");
//删除style=""中的所有样式
//div1.style.cssText = "";
}
</script>
</body>
</html>