1、替换特定字符
<html>
<body>
<script type="text/javascript">
var str="Visit Microsoft!"
document.write(str.replace(/Microsoft/,"W3School"))
</script>
</body>
</html>
2、全局替换
<html>
<body>
<script type="text/javascript">
var str="Welcome to Microsoft! ";
str=str + "We are proud to announce that Microsoft has ";
str=str + "one of the largest Web Developers sites in the world.";
document.write(str.replace(/Microsoft/g, "W3School"));
</script>
</body>
</html>