完成注册功能

1. js文件： onclick函数return True时才提交表单，return False时不提交表单。
2. html文件：
   1. <form>中设置 action和method="post"
   2. <input> 中设置 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’)#获取form中的数据

        判断用户名是否存在

        存到数据库中

        redirect重定向到登录页

js：

function fnRegister() {
    var oUname = document.getElementById("uname");
         var oError = document.getElementById("error-box");
         var oUpass = document.getElementById("upass");
         var oUpass1 = document.getElementById("upass1");

         oError.innerHTML = "<br>";

         if (oUname.value.length<6||oUname.value.length>20){
              oError.innerHTML="用户名要6-12位";
              return false;
                }
                else if(oUname.value.charCodeAt(0)>=48&&(oUname.value.charCodeAt(0)<=57)){
             oError.innerHTML = "首位不能为数字";
           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 = "用户名必须为字母或数字";
                  return false;
                }
         }


          if (oUpass.value.length<6||oUpass.value.length>20){
                    oError.innerHTML="密码至少6-20位";
                   return false;

            }
            if (oUpass1.value!=oUpass.value){
                      oError.innerHTML="密码不一致,请重新输入";
                     return false;
            }
            return true;
        }

html：

{% extends 'base.html' %}
{% block title %}
    Register
{% endblock  %}
{% block head %}

    <link rel="stylesheet" type="text/css" href="{{ url_for('static',filename='css/10.31.css') }}">
    <script src="{{ url_for('static',filename='js/register.js') }}"></script>

{% endblock  %}

{% block main %}
<div class="box">
    <div id="title">RegisterText</div>
    <h3>注册</h3>
    <form action="{{ url_for('register') }}" method="post">
    <div class="input-box">
        账号：<input id="uname" type="text"placeholder="请输入用户名" name="username" >
    </div>
    <div class="input-box">
        密码：<input id="upass" type="password"   placeholder="请输入密码"name="password">
    </div>
    <div class="input-box">
        验证：<input id="upass1" type="password" placeholder="请确认密码" name="password1">
    </div>
    <div id="error-box"><br></div>
    <div class="input-box">
        <button onclick="fnRegister()">注册/Register</button>
        <a href="{{ url_for('login') }}">已注册/Login</a>
    </div>
    </form>
</div>

{% endblock  %}

主页：

from flask import Flask
from flask import render_template,redirect,url_for,request
import config

from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config.from_object(config)
db = SQLAlchemy(app)

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)

# 增加数据
# user = User(username='vae', password='5201314')
# db.session.add(user)
# db.session.commit()
#
# # 查询数据
# user = User.query.filter(User.username == 'vae').first()
# print(user.username,user.password)
#
# #修改数据
# user.password = '250250'
# db.session.commit()

# db.create_all()

@app.route('/')
def index():
    return render_template('base.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)#数据库操作
            db.session.commit()
            return redirect(url_for('login'))#重定向到登录页


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

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