<p>单击按钮将段落中的“blue”替换成“red”</p>

<p id="demo">Mr Blue has a blue house and a blue car.</p>

<button onclick="myFunction()">点我</button>

<script>

function myFunction(){

    var str=document.getElementById("demo").innerHTML;

    var n=str.replace(/blue/g,"red");

    document.getElementById("demo").innerHTML=n;

}

</script>

​