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
from flask_sqlalchemy import SQLAlchemy
import config

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)

db.create_all()

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

@app.route('/login/',methods=['GET','POST'])
def login():
    return render_template('login.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')
        user = User.query.filter(User.username == username).first()
        if user:
            return 'Username existed'
        else:
            user1 = User(username=username, password=password)
            db.session.add(user1)
            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)

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

function MyRegister() {
    var oUname=document.getElementById("uname");
    var oFpass=document.getElementById("fpass");
    var oSpass=document.getElementById("spass");
    var oError=document.getElementById("errorbox");

    //username
    if(oUname.value=="Username"&&oFUpass.value=="Password"&&oSUpass.value=="Password"){
        oError.innerHTML="Please input username";
        return false;
    }else if(oUname.value.length<6||oUname.value.length>12){
        oError.innerHTML="Username must be 6 to 12";
        return false;
    }else if(oUname.value.charCodeAt(0)>=48 && oUname.value.charCodeAt(0)<=57){
        oError.innerHTML="Frist Number";
        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 = "Only letter or number";
                return false;
            }
        }
    }

    //password
    if(oFpass.value!=oSpass.value){
        oError.innerHTML="The password must be the same";
        return false;
    }else if(oFpass.value.length<6||oFpass.value.length>12) {
        oError.innerHTML = "Password must be 6 to 12";
        return false;
    }
    return true;
    // window.alert("Register Successful")
}

{% extends 'base.html' %}

{% block title %}Register{% endblock %}

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

{% block main %}
<div class="login">
    <form action="{{ url_for('regist') }}"  method="post">
        <div class="login-top">
            <h1>Register FORM</h1>
            <input id="uname" name="username" type="text" value="Username" onfocus="this.value = '';" onblur="if (this.value==''){ this.value = 'Username';}">
            <input id="fpass" name="password" type="password" value="Password" onfocus="this.value = '';" onblur="if (this.value==''){ this.value = 'Password';}">
            <input id="spass" type="password" value="Password"  onfocus="this.value = '';" onblur="if (this.value==''){ this.value = 'Password';}">
        </div>
        <div class="login-bottom">
            <div id="errorbox"></div><button onclick="return MyRegister()">Regist</button>
        </div>
    </form>
</div>
{% endblock %}