form验证可以减少查询数据库，所以代码先预先验证，有问题可以返回给前端显示

1.在users文件夹下新建forms.py文件,用来验证用户名和密码是否为空，密码长度是否大于6

# -*- coding: utf-8 -*-
# 作者：神秘藏宝室
# 日期：2018/12/30 21:56
from django import forms

class LoginForm(forms.Form):
    username = forms.CharField(required=True)
    password = forms.CharField(required=True, min_length=6)

2.修改views.py下的LoginView的逻辑,当form出问题返回给前端login_form内容

class LoginView(View):
    def get(self, request):
        return render(request, 'login.html', {})

    def post(self, request):
        login_form = LoginForm(request.POST)
        if login_form.is_valid():
            user_name = request.POST.get("username", "")
            pass_word = request.POST.get("password", "")
            user = authenticate(username=user_name, password=pass_word)
            if user is not None:
                login(request, user)
                return render(request, "index.html")
            else:
                return render(request, "login.html", {"msg": u"用户名或者密码错误!"})
        else:
            return render(request, "login.html", {"login_form": login_form})

3.前端显示错误，显示出错误内容

<div class="form-group marb20 {% if login_form.errors.username %}errorput{% endif %}">
                        <label>用&nbsp;户&nbsp;名</label>
                        <input name="username" id="account_l" type="text" placeholder="手机号/邮箱" />
                    </div>
                    <div class="form-group marb8 {% if login_form.errors.password %}errorput{% endif %}">
                        <label>密&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;码</label>
                        <input name="password" id="password_l" type="password" placeholder="请输入您的密码" />
                    </div>
                    <div class="error btns login-form-tips" id="jsLoginTips">{% for key,error in login_form.errors.items %} {{ error }} {% endfor %}{{ msg }}</div>

以上代码可以实现，错误选项的红框标记，错误问题显示

输入为空

密码长度小于6

正常的用户名密码错误，查询数据库后错误显示

原文地址：https://www.cnblogs.com/Mysterious/p/10200994.html