Detailed example of jQuery using $.ajax for instant verification

Home

Web Front-end

JS Tutorial

Detailed example of jQuery using $.ajax for instant verification_jquery

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

May 16, 2016 pm 03:26 PM

jquery

The example in this article describes how jQuery uses $.ajax for instant verification. Share it with everyone for your reference, the details are as follows:

Here, jQuery and general processing programs are used to instantly verify whether the student number entered by the user is repeated, and a prompt is given when the cursor leaves the input box.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="AddStudent.aspx.cs" Inherits="AddStudent" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
 <title></title>
 <style type="text/css">
  .clsShow
  {
   font-size: 13px;
   border: solid 1px #cc3300;
   padding: 2px;
   display: none;
   margin-bottom: 5px;
   background-color: #ffe0a3;
  }
 </style>
 <script type="text/javascript" src="Scripts/jquery-1.4.2.js"></script>
 <script type="text/javascript">
  $(function () {
   $("#btnSave").click(function () {
    if ($(".clsShow").html().toString() != "")//存在提示信息，则不允许提交表单
     return false;
    else
     return true;
   });
   $("#txtNum").focus(); //输入焦点
   $("#txtNum").keydown(function (event) {
    if (event.which == "13") {//回车键,移动光标到密码框
     $("#txtName").focus();
     $("#txtNum").trigger("blur");
    }
   });
   $("#txtNum").blur(function () {
    //获取学号
    var strTxtName = encodeURI($("#txtNum").val());
    //开始发送数据
    $.ajax
    ({ //请求验证学号是否重复
     url: "Check.ashx", 
     type: "post",
     //传送请求数据
     data: { txtNum: strTxtName },
     success: function (strValue) { //登录成功后返回的数据
      //根据返回值进行状态显示
      if (strValue == "True") {//注意是True,不是true
       $(".clsShow").css("display", "inline");
       $(".clsShow").html("学号已存在，请修改！");
      }
      else {
       $(".clsShow").hide(); //就是把display属性变成none
       $(".clsShow").html("");
      }
     }
    })
   })
  })
 </script>
</head>
<body>
 <form id="form1" runat="server">
 <div>
  学号:<asp:TextBox 
   ID="txtNum" runat="server"></asp:TextBox>
  <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" 
   ControlToValidate="txtNum" ErrorMessage="不能为空"></asp:RequiredFieldValidator>
  <div class="clsShow"></div>
  <br />
  姓名:<asp:TextBox ID="txtName" runat="server"></asp:TextBox>
  <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" 
   ControlToValidate="txtName" ErrorMessage="不能为空"></asp:RequiredFieldValidator>
  <br />
  数学:<asp:TextBox 
   ID="txtMath" runat="server"></asp:TextBox>
  <asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" 
   ControlToValidate="txtMath" ErrorMessage="不能为空"></asp:RequiredFieldValidator>
  <asp:RangeValidator ID="RangeValidator1" runat="server" 
   ControlToValidate="txtMath" ErrorMessage="分数在0-100之间" MaximumValue="100" 
   MinimumValue="0" Type="Integer"></asp:RangeValidator>
  <br />
  英语:<asp:TextBox ID="txtEnglish" runat="server"></asp:TextBox>
  <asp:RequiredFieldValidator ID="RequiredFieldValidator4" runat="server" 
   ControlToValidate="txtEnglish" ErrorMessage="不能为空"></asp:RequiredFieldValidator>
  <asp:RangeValidator ID="RangeValidator2" runat="server" 
   ControlToValidate="txtEnglish" ErrorMessage="分数在0-100之间" MaximumValue="100" 
   MinimumValue="0" Type="Integer"></asp:RangeValidator>
  <br />
  语文:<asp:TextBox ID="txtChinese" runat="server"></asp:TextBox>
  <asp:RequiredFieldValidator ID="RequiredFieldValidator5" runat="server" 
   ControlToValidate="txtChinese" ErrorMessage="不能为空"></asp:RequiredFieldValidator>
  <asp:RangeValidator ID="RangeValidator3" runat="server" 
   ControlToValidate="txtChinese" ErrorMessage="分数在0-100之间" MaximumValue="100" 
   MinimumValue="0" Type="Integer"></asp:RangeValidator>
  <br />
  <asp:Button ID="btnSave" runat="server" Text="保存" onclick="btnSave_Click" />
  <asp:Button ID="btnBack" runat="server" Text="返回" CausesValidation="False" 
   onclick="btnBack_Click" />
  <asp:Label ID="lblMsg" runat="server"></asp:Label>
 </div>
 </form>
</body>
</html>

General handler Check.ashx code:

<%@ WebHandler Language="C#" class="Check" %>
using System;
using System.Web;
public class Check : IHttpHandler {
 public void ProcessRequest (HttpContext context) {
  context.Response.ContentType = "text/plain";
  string num = context.Request["txtNum"].ToString();
  bool result = false;
  if(num=="12")//为了简化代码，没有访问数据库。实际项目应查询数据库。
  {
   result = true;
  }
  context.Response.Write(result);
 }
 public bool IsReusable {
  get {
   return false;
  }
 }
}

I hope this article will be helpful to everyone in jQuery programming.

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

JavaScript: Exploring the Versatility of a Web LanguageApr 11, 2025 am 12:01 AM

JavaScript is the core language of modern web development and is widely used for its diversity and flexibility. 1) Front-end development: build dynamic web pages and single-page applications through DOM operations and modern frameworks (such as React, Vue.js, Angular). 2) Server-side development: Node.js uses a non-blocking I/O model to handle high concurrency and real-time applications. 3) Mobile and desktop application development: cross-platform development is realized through ReactNative and Electron to improve development efficiency.

The Evolution of JavaScript: Current Trends and Future ProspectsApr 10, 2025 am 09:33 AM

The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.

Demystifying JavaScript: What It Does and Why It MattersApr 09, 2025 am 12:07 AM

JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.

Is Python or JavaScript better?Apr 06, 2025 am 12:14 AM

Python is more suitable for data science and machine learning, while JavaScript is more suitable for front-end and full-stack development. 1. Python is known for its concise syntax and rich library ecosystem, and is suitable for data analysis and web development. 2. JavaScript is the core of front-end development. Node.js supports server-side programming and is suitable for full-stack development.

How do I install JavaScript?Apr 05, 2025 am 12:16 AM

JavaScript does not require installation because it is already built into modern browsers. You just need a text editor and a browser to get started. 1) In the browser environment, run it by embedding the HTML file through tags. 2) In the Node.js environment, after downloading and installing Node.js, run the JavaScript file through the command line.

How to send notifications before a task starts in Quartz?Apr 04, 2025 pm 09:24 PM

How to send task notifications in Quartz In advance When using the Quartz timer to schedule a task, the execution time of the task is set by the cron expression. Now...

In JavaScript, how to get parameters of a function on a prototype chain in a constructor?Apr 04, 2025 pm 09:21 PM

How to obtain the parameters of functions on prototype chains in JavaScript In JavaScript programming, understanding and manipulating function parameters on prototype chains is a common and important task...