js正则表达式（简单例子）

<div id="my">abcd345mkjhe4hbwhjg4gghrtjsehhellorut784huhgworldf87dytejk;</div>
<script>
var my = document.getElementById('my');
var text = my.innerHTML;
re = /\w+(hello)\w+(world)\w+/ig;  //这里不要加引号
var newt = text.replace(re,'<font color="red">$1</font><font color="red">$2</font>'); //替换内容必须加引号
my.innerHTML = newt;
</script>