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)

regist.js

function myLogin() {
            var oUname = document.getElementById("umane");
            var oError = document.getElementById("error_box");
             var oUpass = document.getElementById("upass");
             var  oUpass1= document.getElementById("userpass1");
               var isError = true;
            oError.innerHTML = "<br>";

     //oUname

     if (oUname.value.length>12 || oUname.value.length<6){
            oError.innerHTML = "name:6-12";
            isError=false;
             return isError;
         }
         else if((oUname.value.charCodeAt(0)>=48) && oUname.value.charCodeAt(0)<=57){

            oError.innerHTML = "首字母不能是数字";
             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 = "只能包含字母和数字";
                    isError=false;
                    return isError;
                }
            }


            if(upass.value.length>12 || upass.value.length<6){
                oError.innerHTML="password;6-12";
                isError=false;
                return isError;
            }
            if(oUpass.value != oUpass1.value){
                oError.innerHTML="两次密码输入不一致";
                isError=false;
                return isError;
            }
             window.alert("注册成功 ！")
              return isError

regist.HTML

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

<div class="bigbox">
      <div class="box">
          <h2>注册</h2>
          <form action="{{ url_for('regist') }}"method="post">
       <div class="input_box">
           输入账户：<input id="umane"type="text"placeholder="请输入用户名">
       </div>
        <div class="input_box">
           输入密码：<input id="upass"type="password"placeholder="请输入密码">
       </div>
          <div class="input_box">
           再输密码：<input id="userpass1" type="password" placeholder="请再次输入密码">
    </div>
          <div id="error_box"><br></div>
          <div class="input_box">
              <button onclick="myLogin()">注册</button>

          </div>
              </form>
               </div>

    {% endblock %}