11.21

1. js:设置return

   function foLogin() {
               var oUname = document.getElementById("uname");
               var oError = document.getElementById("error_box");
               var oUpass = document.getElementById("upass");
               var oUpass1=document.getElementById("upass1");
               var isoError = true;
               oError.innerHTML = "<br>";
   
               if (oUname.value.length < 6 || oUname.value.length > 20) {
                   oError.innerHTML = "用户名要6-20位";
                   isoError = false;
                   return isoError;
               }else if((oUname.value.charCodeAt(0)<=48)&&(oUname.value.charCodeAt(0)>=57)){
                   oError.innerHTML="首字母不能为数字";
                   isoError = false;
                   return isoError;
               }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";
                       isoError = false;
                       return isoError;
                   }
               }
   
               if (oUpass.value.length < 6 || oUpass.value.length > 20){
                   oError.innerHTML = "密码要6-20位";
                   isoError = false;
                   return isoError;
               }
               if(oUpass.value()!=oUpass1.value()){
                   oError.innerHTML="两次密码不一致";
                   isoError = false;
                   return isoError;
               }
               window.alert("注册成功！！")
       return true;
   
           }

   html:设置

   1. form
   2. input

       <form action="{{ url_for('denglu') }}" method="post">
          <div id="tittle"><h2 align="center">登录</h2></div>
          <div class="input_box">
              账户： <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 id="error_box"><br></div>
          <div class="input_box">
              <button onclick="foLogin()">登录</button>
          </div>
      
          <button type="button" onclick="foLogin()"><a href="zhuce.html">注册</a></button>
          </form>

      py:

      1. @app.route设置methods
      2. GET
      3. POST

         @app.route('/denglu',methods=['GET','POST'])
         def denglu():
             if request.method=='GET':
                 return render_template('denglu.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:
                     if user.password == password:
                         return redirect(url_for('shouye'))
                     else:
                         return u'password error'
                 else:
                     return 'username is not existed'

         1. 读取表单数据
         2. 查询数据库
            1. 用户名密码对：
               1. 记住用户名
               2. 跳转到首页
            2. 用户名密码不对：
               1. 提示相应错误

                  

                  session：

                  1. 从`flask`中导入`session`
                  2. 设置`SECRET_KEY`
                  3. 操作字典一样操作`session`：增加用户名`session['username']=`username

                     import os
                     
                     SELECT_KEY=os.urandom(24)
                     
                     SQLALCHEMY_DATABASE_URI='mysql+pymysql://root:@127.0.0.1:3306/mis3?charset=utf8'
                     SQLALCHEMY_TRACK_MODIFICATIONS=False