Implementing CheckBox to select all and none based on JQuery_jquery

So I tried to write one by referring to the examples on the Internet, and achieved the effect I wanted. In fact, this is also a very simple example. I hope everyone can point out the deficiencies in it.
Post the code below for everyone to see

Copy the code The code is as follows:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="checkAll.aspx.cs" Inherits="checkAll" %>







< ;/head>