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:存在报错

  不存在，存到数据库中

       redirect重定向到登录页

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('/regist/',methods=['GET','POST'])
def regist():
    if request.method=='GET':
        return render_template('regist.html')
    else:
        username=request.form.get('username')
        password=request.form.get('password')
        nickname=request.form.get('nickname')
        user=User.query.filter(User.username==username).first()
        if user:
            return u'username existed'
        else:
            user=User (username=username,password=password,nickname=nickname)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for('login'))



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


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

SQLALCHEMY_DATABASE_URI = 'mysql+pymysql://root:@localhost:3306/mis_db?charset=utf8'
SQLALCHEMY_TRACK_MODIFICATIONS = False

function myLogin(){
            var uName=document.getElementById("name");
            var uError=document.getElementById("error_box");
            var upass = document.getElementById("password");
            var uphone = document.getElementById("userphone");
            var upass1 = document.getElementById("password1");
            uError.innerHTML = "<br>"
            //uname
            if(uName.value.length>12 || uName.value.length<6){
                uError.innerHTML="Username 6-12 bits";
                return false;
            }else if((uName.value.charCodeAt(0)>=48)&& uName.value.charCodeAt(0)<=57){
                uError.innerHTML="The first letter cannot be numeric";
                return false;
            }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 = "only letter or number.";
                    return false;
                }
            }


            if(upass.value.length>12 || upass.value.length<6){
                uError.innerHTML="password 6-12 bits";
                return false;
            }
            if(upass.value != upass1.value){
                uError.innerHTML="The password input is inconsistent";
                return false;
            }
            if(uphone.value.length>11 || uphone.value.length<11){
                uError.innerHTML="phone number at least 11";
                return false;
            }
        return true
            window.alert("注册成功 ！")

        }

{% extends 'base.html' %}

{% block title %}注册{% endblock %}

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

{% block main %}
<div class="aa" >
    <div class="login" ><h2>注册/Register</h2></div>
    <form action="{{ url_for('regist') }}"method="post">
    <div class="aa1" >
        <input id="name" type="text"placeholder="请输入用户名"name="username"><br>
        <input id="nickname" type="text"placeholder="昵称"name="nickname"><br>
        <input id="password" type="password"placeholder="请输入密码"name="password"><br>
        <input id="password1" type="password"placeholder="请再次输入密码"><br>

    </div>
        <div id="error_box"><br></div>
      <div class="aa2" >
         <button onclick="return myLogin()">Submit</button>
         <button type="button" onclick=window.alert("是否取消登录！")>Cancel</button>

<body background="https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1510743628&di=571738b7d2f56efdc88e82b5404a756e&imgtype=jpg&er=1&src=http%3A%2F%2Fimg0.pconline.com.cn%2Fpconline%2F1612%2F11%2F8637260_126a9835.jpg"style="background-repeat:no-repeat;background-size: 100% 100%; background-attachment: fixed;">
</body>
    </div>
        </form>
</div>
{% endblock %}