难道一定要用css定义颜色?
<!DOCTYPE html>
<html>
<head>
<title>.class选择器</title>
<script src="http://libs.baidu.com/jquery/1.9.0/jquery.js" type="text/javascript"></script>
</head>
<body>
<div class="red">立正,向我这边看齐</div>
<div class="green">我先歇歇脚</div>
</body>
<script type="text/javascript">
var $redHTML = $(".red").html();
$(".green").html($redHTML);
$(".red").css("color","red");
$(".green").css("color","green");
</script>
</html>