效果如下：
完整代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
.res {
width: 200px;
height: 200px;
border: 1px solid #ccc;
}
</style>
<title>Document</title>
</head>
<body>
<h3>敏感过滤器</h3>
<textarea name="" id="" cols="30" rows="10"></textarea>
<input type="submit">
<p class="res"></p>
<script>
let text = document.querySelector('textarea');
let sub = document.querySelector('input');
let p = document.querySelector('.res');
let reg = /tmd|md/g;
sub.addEventListener('click', function () {
p.innerHTML = text.value.replace(reg, '**');
})
</script>
</body>
</html>
