Registration features (form validation)

<script type="text/javascript">
            function check() {
                var username = document.getElementById("username");
                var email = document.getElementById("email").value;
                var p = /^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/; //邮箱匹配的正则表达式
                var password = document.getElementById("password").value;
                var rePassword = document.getElementById("rePassword").value;
                var isPass = true;
    
                var usernameMsg = document.getElementById("usernameMsg");
                 Var emailMsg = document.getElementById ( "emailMsg" );
                 var passwordMsg = document.getElementById ( "passwordMsg" );
                 //             the console.log (username); 
                //             the console.log (username.value); 
    
                var length = username .value.length;
                 IF (length <length ||. 3>. 6 ) {
                     //                 Alert ( "username must be 3-6"); 
                    usernameMsg.innerText = "username must be 3-6" ; 
                    isPass = to false ;
                } else{ 
                    UsernameMsg.innerText = "" ; 
                } 
    
                IF (p.test (In Email) == to false ) {
                     //                 Alert ( "mailbox format is incorrect"); 
                    emailMsg.innerText = "mailbox format is incorrect" ; 
                    isPass = to false ; 
                } the else { 
                    emailMsg.innerText = "" ; 
                } 
    
                IF (password.length <||. 6 password.length> 10 ) {
                     //                 Alert ( "password must be between 6-10");
                    passwordMsg.innerText = "password must be between 6-10" ; 
    
                    isPass = to false ; 
                } the else {
                     IF (password =! rePassword) {
                         //                     Alert ( "Enter the password twice inconsistent!"); 
                        passwordMsg.innerText = "two enter the password twice inconsistent! " ; 
                        isPass = to false ; 
                    } the else { 
                        passwordMsg.innerText =" " ; 
                    } 
                } 
                //            if(isPass==false){
                //                return false;
                //            }else{
                //                return true;
                //            }
                return isPass;
            }
    
            function checkUserName(uesrname) {
                var usernameMsg = document.getElementById("usernameMsg");
                var length = username.value.length;
                if(length < 3 || length > 6) {
                    usernameMsg.innerText = "用户名长度必须是3-6位";
                } else {
                    usernameMsg.innerText = "";
                }
            }
    
            function checkEmail(email) {
                var emailMsg = document.getElementById("emailMsg");
                var p = /^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/;
                if(p.test(email.value) == false) {
                    emailMsg.innerText = "邮箱格式不正确";
                } else {
                    emailMsg.innerText = "";
                }
            }
            
            function checkPassword(){
                var password = document.getElementById("password");
                var passwordMsg = document.getElementById("passwordMsg");
                var rePassword = document.getElementById("rePassword").value;
                
                
                if(password.value.length < 6 || password.value.length > 10) {
                    passwordMsg.innerText = "密码必须在6-10之间";
                } else {
                    passwordMsg.innerText = "";
                    if(password.value != rePassword) {
                        passwordMsg.innerText= "Not match the password twice!" ; 
                    } The else { 
                        passwordMsg.innerText = "" ; 
                    } 
                } 
            }
         </ Script>

<!DOCTYPE html>
<html>

    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    

    <body>
        <form action="register.jsp" onsubmit="return check()">
            <table border="1" width="500px" height="500px">
                <tr>
                    <td colspan="2" align="center">注册</td>
                </tr>
                <tr>
                    <td align="right">用户名:</td>
                    <td align="left">
                        <input type="text" id="username" onblur="checkUserName(this)" />
                        <font color="red" id="usernameMsg"></font>
                    </td>

                </tr>
                <tr>
                    <td align="right">邮箱:</td>
                    <td align="left">
                        <input type="text" id="email" onblur="checkEmail(this)" />
                        <font color="red" id="emailMsg"></font>
                    </td>
                </tr>
                <tr> 
                    <td align="right " >td</Password:>
                    <td align="left">
                        <input type="password" id="password" onblur="checkPassword()"/>
                        <font color="red" id="passwordMsg"></font>
                    </td>
                </tr>
                <tr>
                    <td align="right">重复密码:</td>
                    <td align="left">
                        <input type="password" id="rePassword" onblur="checkPassword()"/>
                    </td>
                </tr>
                <tr>
                    <td colspan="2" align="center"><input type="submit" name="注册" /></td>
                </tr>
            </table>
        </form>
    </body>