完成註冊功能

1. js文件： onclick函數return True時才提交表單，return False時不提交表單。
2. html文件：
   1. <form>中設置 action和method="post"
   2. <input> 中設置 name
3. 主py文件中：
   1. from flask import  request, redirect, url_for
   2. @app.route('/regist/', methods=['GET', 'POST’])

def regist():

   if request.method == 'GET':

        return render_template('regist.html')

   else:

        username = request.form.get(‘username’)#獲取form中的數據

        判斷用戶名是否存在:存在報錯

  不存在，存到數據庫中

       redirect重定向到登陸頁

zhuce.html

{% extends 'base.html' %}
{% block title %}註冊{% endblock %}

{% block head %}
<link rel="stylesheet"  href="{{ url_for('static',filename='css/login.css') }}">
    <script src="{{url_for('static',filename='js/login.js') }}"></script>
{% endblock %}
{% block main %}

<div class="Outbox">
      <div class="box">
          <h2>用戶註冊</h2>
          <form method="post" action="{{ url_for('zhuce') }}">
       <div class="input_box">
          輸入帳號：<input id="name"type="text"placeholder="請輸入用戶名">name="username"><br>
       </div>
        <div class="input_box">
            輸入密碼：<input id="password"type="password"placeholder="請輸入密碼">name="password"><br>
       </div>
          <div class="input_box">
           確認密碼：<input id="password1" type="password" placeholder="請再次輸入密碼">
    </div>
          <div id="error_box"><br></div>
          <div class="input_box">
              <button onclick="myLogin()">註冊</button>
<button onclick=window.alert("取消註冊") type="submit" class="btn btn-primary btn-block btn-large">返回</button>

          </div>
      </div>

{% endblock %}

zhuce.js

function myLogin(){
            var oUname = document.getElementById("name");
            var oError = document.getElementById("error_box");
             var oUpass = document.getElementById("password");
             var  oUpass1= document.getElementById("password1");
            oError.innerHTML = "<br>"
     //oUname
        if (oUname.value.length>12 || oUname.value.length<6){
            oError.innerHTML = "用戶名爲6到12位數";
            return false;
         }
         else if((oUname.value.charCodeAt(0)>=48) && oUname.value.charCodeAt(0)<=57){

            oError.innerHTML = "首字母不能是數字";
            return false;
        }
        else for(var i=0; i<oUname.value.length;i++) {

     if((oUname.value.charCodeAt(i)<48 || oUname.value.charCodeAt(i)>57)&&(oUname.value.charCodeAt(i)<97 || oUname.value.charCodeAt(i)>122 )){
                    oError.innerHTML = "只能包含字母和數字";
                    return false;
                }
            }

       if(upass.value.length>12 || upass.value.length<6){
                oError.innerHTML="密碼爲6到12位數";
                return false;
            }
            if(oUpass.value != oUpass1.value){
                oError.innerHTML="兩次密碼輸入不一致";
                return true;
            }
             window.alert("已成功註冊")

        }

py

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)

class User(db.Model):
    __table__name = '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)
    nickname = db.Column(db.String(50))

#db.create_all()



@app.route('/')
def index():
    return render_template('index.html')

@app.route('/login/',methods=['GET','POST'])
def login():
    return render_template('login.html')

@app.route('/zhuce/',methods=['GET','POST'])
def zhuce():
    if request.method =='GET':
        return  render_template('zhuce.html')
    else:
        usern = request.form.get('name')
        teln = request.form.get('password')
        passw = request.form.get('password1')
        user = User.query.filter(User.username==usern).first()
        if user:
            return 'username existed'
        else:
            user= User(username=usern,tel=teln,password=passw)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for('login'))


@app.route('/question/',methods=['GET','POST'])
def question():
    return render_template('question.html')

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