jsp页面新建表单：
说明：action路径需要修改成你自己的
<form id="signForm" action="doSignIn">
<input type="email" id="email" placeholder="Email address" name="email" value="" required autofocus>
<input type="password" id="password1" placeholder="Your Password" name="password1" value="" required>
<input type="password" id="password2" placeholder="Sure Password" name="password2" value="" required>
<div id="errorMessage"></div>
<button type="button" onclick="checkPassword()">注 册</button>
</form>
javascript代码：
<script>
function checkPassword(){
var email = document.getElementById("email").value;
var password1 = document.getElementById("password1").value;
var password2 = document.getElementById("password2").value;
var errorMessage;
if(email==""){
errorMessage = document.getElementById("errorMessage");
errorMessage.innerHTML="请输入邮箱!";
}else if(password1 == ""|| password2 == ""){
errorMessage = document.getElementById("errorMessage");
errorMessage.innerHTML="请输入密码!";
}else if(password1 != password2){
errorMessage = document.getElementById("errorMessage");
errorMessage.innerHTML="密码不一致!";
}else{
document.getElementById("signForm").submit();
}
}
</script>
java后台
说明：java程序可以用HttpServletRequest request获得数据，Servlet或者框架都看你自己的项目，return 也看你自己的情况修改
public String doSignIn(HttpServletRequest request){
String username = request.getParameter("email");
String password = request.getParameter("password1");
System.out.println(username+"\n"+password);//替换SQL操作
return "success";
}