```
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
*{margin:0;padding:0;}
#div{width:410px;height:400px;background:#46a3ff;padding-left:16px;
padding-top:20px;}
input{
outline:none;
box-sizing:border-box;padding-left:15px;}
textarea{
outline:none;resize : none;
box-sizing:border-box;padding-left:15px;padding-top:5px;}
.name{width:200px;height:30px;margin-left:8px;border:1px solid #ffc1e0;border-radius:8px;}
.pwd{width:200px;height:30px;
margin-left:8px;border:1px solid #ffc1e0;border-radius:8px;}
.email{width:200px;height:30px;margin-left:8px;border:1px solid #ffc1e0;border-radius:8px;}
.txt{
width:280px;height:70px;margin-left:8px;border:1px solid #ffc1e0;border-radius:8px;}
.sub{width:100px;height:30px;padding-left:0px;
border:none;
border-radius:5px;background:#ffd0ff;}
.sub:hover{background:#ffaad5;}
.div{
width:200px;height:30px;margin:0 auto;box-sizing:border-box;padding-left:45px;padding-top:5px;color:#8600ff;font-weight:bold;}
</style>
</head>
<body>
<div id="div">
<form>
<label>用戶名:</label>
<input type="text" class="name" id="name">
<div id="sp" class="div"></div>
<label>密 碼:</label>
<input type="password" class="pwd" id="pwd">
<div id="sp1" class="div"></div>
<label>郵 箱:</label>
<input type="text" class="email" id="email">
<div id="sp2" class="div"></div>
<label>愛 好:</label>
<textarea rows="5" cols="40" class="txt" id="txt"></textarea>
<div id="sp3" class="div"></div>
<input type="button" class="sub" value="注冊" id="sub">
</form>
</div>
<script type="text/javascript">
var sub = document.getElementById('sub');
sub.onclick=function(){
//驗證用戶名是否為空,如果為空，給出提示信息
var val = document.getElementById('name').value;
var rel = document.getElementById('name').value.length;
//console.log(val.length);
if(val == ""){
document.getElementById("sp").innerHTML = "用戶名不能為空！";
}else if( rel <= 5 || rel > 10){
document.getElementById("sp").innerHTML = "格式不正確！";
}
//驗證密碼是否為空，為空則給出提示信息
var rel = /^[A-Za-z0-9]{6,10}$/;
var val1 = document.getElementById('pwd').value;
if(val1 == ""){
document.getElementById("sp1").innerHTML = "請輸入密碼！";
}else if(!rel.test(val1)){
document.getElementById("sp1").innerHTML = "密碼不符合規范！";
}
//驗證郵箱是否為空和郵箱的格式是否正確
var reg = /^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/;
var val2 = document.getElementById('email').value;
if(val2 == ""){
document.getElementById("sp2").innerHTML = "請輸入郵箱！";
}else if(!reg.test(val2)){
document.getElementById("sp2").innerHTML = "郵箱格式不正確！";
}
//驗證內容是否為空
var val3 = document.getElementById('txt').value;
if(val3 == ""){
document.getElementById("sp3").innerHTML = "請輸入內容！";
}
}
//當用戶名的文本框觸發鍵盤事件，提示信息去除
document.getElementById('name').onkeyup=function(){
document.getElementById('sp').innerHTML = " ";
}
// //當密碼框觸發鍵盤事件，提示信息去除
document.getElementById('pwd').onkeyup=function(){
document.getElementById('sp1').innerHTML = " ";
}
// //當郵箱文本框觸發鍵盤事件，提示信息去除
document.getElementById('email').onkeyup=function(){
document.getElementById('sp2').innerHTML = " ";
}
// //當文本域觸發鍵盤事件，提示信息去除
document.getElementById('txt').onkeyup=function(){
var leng = document.getElementById('txt').value.length;
if(leng>20){
document.getElementById("sp3").innerHTML = "已超過最大內容！";
}else{
document.getElementById('sp3').innerHTML = " ";
}
}
</script>
</body>
</html>
```
