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

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

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)
    nickname = db.Column(db.String(50))


db.create_all()


'''
user=User.query.filter(User.username=='mis1',password='mis1')
db.session.add(user)
db.session.commit()

user=User.query.filter(User.username=='mis1').first()
user.password='123456'
user.username='mis1'
print(user.username,user.password)
db.session.commit()
'''

@app.route('/')
def index():
    context={'question':Question.query.order_by('-creat_tiome').all}
    return render_template('index.html',**context)

@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 'username existed'
        else:
            user=User(username=username,password=password,nickname=nickname)
            db.seesion.add(user)
            db.seesion.commit()
            return  redirect(url_for('login'))
    return render_template('regist.html')

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

function fnLogin() {
    var oUname = document.getElementById("uname")
    var oName = document.getElementById("nname")
    var oError = document.getElementById("error_box")
    var oUpass = document.getElementById("upass")
    var oUpass1=document.getElementById("upass1")
    var isError=true;
    oError.innerHTML = "<br>"
    //unname
    if (oUname.value.length < 6 || oUname.value.length > 20) {
        oError.innerHTML = "用户名6-20位";
        isError=false;
        return;isError;
    } else if ((oUname.value.charCodeAt(0) >= 48) && (oUname.value.charCodeAt(0) <= 57)) {
        oError.innerHTML = "first letter.";
        isError=false;
        return;isError;
    } 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";
            isError=false;
            return;isError;
        }
    }

    //upass
    if (oUpass.value.length < 6 || oUpass.value.length > 12) {
        oError.innerHTML = "密码6-12位"
        isError=false;
        return;isError;
    }
    //uupass
    if (oUpass.value!=oUpass1.value) {
        document.getElementById("error_box").innerHTML="两次密码不一致"
        isError=false;
        return;isError;
    }
    //name
    if (oName.value.length < 3 || oName.value.length > 6) {
        oError.innerHTML = "昵称3-6位";
        isError=false;
        return;isError;
    }else for (var i = 0; i < oUname.value.length; i++){
        if ((oName.value.charCodeAt(i) < 48) || (oName.value.charCodeAt(i) > 57) && (oName.value.charCodeAt(i) < 97) || (oName.value.charCodeAt(i) > 122)) {
            oError.innerHTML = "only letter or number";
            isError=false;
            return;isError;
        }
    }
    return isError;
                window.alert("登陆成功！")


        }

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

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

{% block main %}
<div class="box">
    <h2>广州商学院</h2>
   <h3>注册</h3>
    <form action="{{url_for('regist')}}" method="post"></form>
    <div class="input_box">
        <input id="uname" type="text" placeholder="请输入用户名" name="username" style="width:300px">
    </div>
    <div class="input_box">
        <input id="upass" type="password" placeholder="请输入密码" name="password" style="width:300px"><br>
        <input id="upass1" type="password" placeholder="请重复输入密码" style="width:300px">
    </div>
    <div class="input_box">
        <input id="nname" type="password" placeholder="请输入昵称" name="nickname" style="width:300px">
    </div>
    </div>
    <br>
    <div id="error_box"><br></div>
    <div class="input_box">
        <button onclick="fnLogin()">注册</button><br>

    </div>
</div>
{% endblock %}