from flask import Flask,render_template,request,redirect,url_for,session
from flask_sqlalchemy import SQLAlchemy
import config

app = Flask(__name__)
app.config.from_object(config)
db=SQLAlchemy(app)

db = SQLAlchemy(app)
# 创建用户模型
class User(db.Model):
    __tablename__ = ‘user‘
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    username = db.Column(db.String(20), nullable=False)
    password = db.Column(db.String(20), nullable=False)

#db.create_all()


@app.route(‘/‘)
def homepage():
    return render_template("homepage.html")

@app.route(‘/login/‘)
def login():
    return render_template("login.html")

@app.route("/register/",methods=[‘GET‘,‘POST‘])
def register():
    if request.method == "GET":
        return render_template("register.html")
    else:
        username = request.form.get("username")
        password = request.form.get("password")
        user = User.query.filter(User.username == username).first()
        if user:
            return ‘username existed.‘
        else:
            user = User(username=username, password=password)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for(‘login‘))


@app.route("/question/")
def question():
    return render_template("question.html")

if __name__ == ‘__main__‘:
    app.run(debug=True)

{% extends‘index.html‘ %}
 {% block title %}
     注册
        {% endblock %}
{% block head %}
    <link href="{{ url_for(‘static‘,filename=‘CSS/designR.css‘) }}" rel="stylesheet" type="text/css">
    <script src="{{ url_for(‘static‘,filename=‘JS/confirmR.js‘) }}"></script>
{% endblock %}

{% block main %}
<div class="box" >
    <div class="jar" ><h2>欢迎注册</h2></div>
    <form action="{{ url_for("register") }}" method="post">
        <div class="input_box">
            账号　     <input id="name" name="username"type="text" placeholder="请输入用户名">   </div><br>
        <div class="input_box">
            密码　     <input id="password" name="password"type="password" placeholder="请输入密码"></div><br>
         <div class="input_box">
            再输入     <input id="passwordagain" name="passwordagain"type="password" placeholder="请再次输入密码"></div><br>
        <div id="error_box"><br></div>
         <div class="ja">
            <button onclick="fnLogin()" >注册</button></div>
    </form></div>

{% endblock %}

function fnLogin() {
        var uname = document.getElementById("name")
        var uError = document.getElementById("error_box")
        var upassword = document.getElementById("password")
        var upasswordagain = document.getElementById("passwordagain")
        var isError =true;
         if(uname.value.length<6 || uname.value.length >20){
        uError.innerHTML="用户名应为6到20字符";
        isError = false;
         return;
    }else if ((uname.value.charCodeAt(0)>=48) && (uname.value.charCodeAt(0)<=57)){
        uError.innerHTML="第一位只能是字母";
        isError = false;
        return ;
    } else for (var i=0 ; i<uname.value.length;i++){
        if (uname.value.charCodeAt(i)<48 || (uname.value.charCodeAt(i)>57)&&(uname.value.charCodeAt(i)<97)|| uname.value.charCodeAt(i)>122){
            uError.innerHTML="用户名只能为数字或者字母";
           isError = false;
         return;
        }
    }
    if(upassword.value.length<6 || upassword.value.length>12){
        uError.innerHTML="密码应为6到20字符";
       isError = false;
         return;
    }
    if (upasswordagain.value!=upassword.value ) {
        uError.innerHTML = "重新输入你的密码";
       isError = false;
         return;
    }
    return isError;
    window.alert("注册成功")
}