Web Front-end
JS Tutorial
Use jQuery and AJAX technology to regularly update a certain column of GridView data_jquery
Use jQuery and AJAX technology to regularly update a certain column of GridView data_jquery
I saw a problem: regularly update the status text in a column of the GridView. An idea immediately came to mind: GridView will eventually generate a table, so we update the columns of the table through Ajax on the page to achieve the effect of ajax updating GridView.
Detailed implementation:
Prepare an xml file to store the data to be updated, start a timer in the page, and call a function every 5 seconds. The function uses $.ajax to obtain the data in the xml, parse the xml, and traverse the table. Rows that match the data to be updated are updated.
getuserlist.xml
Define the root node of a UserList. Each UserItem below corresponds to a piece of data. UID can be understood as the primary key, and UStatus is the latest status.
<?xml version="1.0" encoding="utf-8" ?> <UserList> <UserItem><UID>1</UID><UStatus>关闭</UStatus></UserItem> <UserItem><UID>2</UID><UStatus>关闭</UStatus></UserItem> <UserItem><UID>3</UID><UStatus>开放</UStatus></UserItem> </UserList>
test.html
The specific logic is written here.
<html>
<head>
<title>Ajax Update Table Column</title>
<script src="jquery-1.3.1.min.js" type="text/javascript"></script>
<script type="text/javascript">
window.onload=function(){
//每隔5秒检查一下数据
window.setInterval(checkStatus,5000);
};
//检查数据
function checkStatus(){
//ajax请求数据
$.ajax({
//换成你的文件，构造xml格式的数据就行了
url: 'getuserlist.xml',
//请求类型
type: 'GET',
//数据格式
dataType: 'xml',
//超时时间：1秒
timeout: 2000,
//加载数据发生错误
error:function (XMLHttpRequest, textStatus, errorThrown) {
alert("XMLHttpRequest="+XMLHttpRequest.responseText+"\ntextStatus="+textStatus+"\nerrorThrown="+errorThrown);
},
//成功加载数据
success: function(xml){
//遍历表格的行，需要给表格定义一个ID
$("#userListTable tr").each(function(){
//获取行的第一列，这里边保存了XML中对应的UID信息
var trID=$(this).find("td").eq(0).text();
//数据的新状态
var trStatus="";
//遍历xml中的UserItem
$(xml).find("UserList > UserItem").each(function(){
//获取UID和UStatus的值
var uid = $(this).find("UID").text();
var ustatus = $(this).find("UStatus").text();
//比对当前行的ID和UID，如果相等，给数据的新状态赋值
if(trID==uid){
trStatus=ustatus;
}
});
//如果数据的新状态不为空，则更新单元格中现实的文本
if(trStatus!=""){
$(this).find("td").eq(2).text(trStatus);
}
});
}
});
}
</script>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<!--
这个表格有三列
ID：数据的ID，相当于主键，用于从xml中查询新数据
Name：只是显示
Status：要更新的列
-->
<table border="1" id="userListTable">
<tr><th>ID</th><th>Name</th><th>Status</th></tr>
<tr><td>1</td><td>张三</td><td>开放</td></tr>
<tr><td>2</td><td>李四</td><td>开放</td></tr>
<tr><td>3</td><td>王五</td><td>开放</td></tr>
</table>
</body>
</html>
Finally, place the required files under a browsable site and open test.html.
Wait for 5 seconds and you will see the effect.
Due to a problem with IE, opening it directly in a folder will cause the problem of being unable to parse the xml file (parsererror), so it is recommended to put it under a site that can be run, or open it with another browser.
PS: GridView is the successor control of DataGrid. In framework 2, although DataGrid still exists, GridView has come to the forefront of history, and the trend of replacing DataGrid is unstoppable. GridView and DataGrid have similar functions. They both display data from the data source on the web page, and display a row of data in the data source, that is, a record, as a row in the output table on the web page.
Compared with DataGrid, GridView has the following advantages and is richer in functions. Because it provides a smart tag panel (that is, show smart tag), it is easier to use and more convenient. Commonly used operations such as sorting, paging, updating, and deletion can be implemented with zero code! With the PagerTemplate attribute, the user navigation page can be customized, which means that the control of paging is more arbitrary. GridView and DataGrid also have many differences in event models. The DataGrid control triggers a single event, while the GridView control triggers two events, one before the operation and one after the operation. The event before the operation is multiple. ***ing event, the event after the operation is multiple ***ed events, such as Sorting event and sorted event, RowDeleting and RowDeleted event.
The way to refresh the interface of Listview and Gridview is to call adapter.notifyDataSetChanged() to refresh the interface.
However, this method has its drawbacks. It refreshes all the data in the interface, regardless of whether the data has changed or not.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1374
52
How to use PUT request method in jQuery?
Feb 28, 2024 pm 03:12 PM
How to use PUT request method in jQuery? In jQuery, the method of sending a PUT request is similar to sending other types of requests, but you need to pay attention to some details and parameter settings. PUT requests are typically used to update resources, such as updating data in a database or updating files on the server. The following is a specific code example using the PUT request method in jQuery. First, make sure you include the jQuery library file, then you can send a PUT request via: $.ajax({u
How to get variables from PHP method using Ajax?
Mar 09, 2024 pm 05:36 PM
Using Ajax to obtain variables from PHP methods is a common scenario in web development. Through Ajax, the page can be dynamically obtained without refreshing the data. In this article, we will introduce how to use Ajax to get variables from PHP methods, and provide specific code examples. First, we need to write a PHP file to handle the Ajax request and return the required variables. Here is sample code for a simple PHP file getData.php:
jQuery Tips: Quickly modify the text of all a tags on the page
Feb 28, 2024 pm 09:06 PM
Title: jQuery Tips: Quickly modify the text of all a tags on the page In web development, we often need to modify and operate elements on the page. When using jQuery, sometimes you need to modify the text content of all a tags in the page at once, which can save time and energy. The following will introduce how to use jQuery to quickly modify the text of all a tags on the page, and give specific code examples. First, we need to introduce the jQuery library file and ensure that the following code is introduced into the page: <
Use jQuery to modify the text content of all a tags
Feb 28, 2024 pm 05:42 PM
Title: Use jQuery to modify the text content of all a tags. jQuery is a popular JavaScript library that is widely used to handle DOM operations. In web development, we often encounter the need to modify the text content of the link tag (a tag) on the page. This article will explain how to use jQuery to achieve this goal, and provide specific code examples. First, we need to introduce the jQuery library into the page. Add the following code in the HTML file:
PHP and Ajax: Building an autocomplete suggestion engine
Jun 02, 2024 pm 08:39 PM
Build an autocomplete suggestion engine using PHP and Ajax: Server-side script: handles Ajax requests and returns suggestions (autocomplete.php). Client script: Send Ajax request and display suggestions (autocomplete.js). Practical case: Include script in HTML page and specify search-input element identifier.
PHP vs. Ajax: Solutions for creating dynamically loaded content
Jun 06, 2024 pm 01:12 PM
Ajax (Asynchronous JavaScript and XML) allows adding dynamic content without reloading the page. Using PHP and Ajax, you can dynamically load a product list: HTML creates a page with a container element, and the Ajax request adds the data to that element after loading it. JavaScript uses Ajax to send a request to the server through XMLHttpRequest to obtain product data in JSON format from the server. PHP uses MySQL to query product data from the database and encode it into JSON format. JavaScript parses the JSON data and displays it in the page container. Clicking the button triggers an Ajax request to load the product list.
How to tell if a jQuery element has a specific attribute?
Feb 29, 2024 am 09:03 AM
How to tell if a jQuery element has a specific attribute? When using jQuery to operate DOM elements, you often encounter situations where you need to determine whether an element has a specific attribute. In this case, we can easily implement this function with the help of the methods provided by jQuery. The following will introduce two commonly used methods to determine whether a jQuery element has specific attributes, and attach specific code examples. Method 1: Use the attr() method and typeof operator // to determine whether the element has a specific attribute
PHP and Ajax: Ways to Improve Ajax Security
Jun 01, 2024 am 09:34 AM
In order to improve Ajax security, there are several methods: CSRF protection: generate a token and send it to the client, add it to the server side in the request for verification. XSS protection: Use htmlspecialchars() to filter input to prevent malicious script injection. Content-Security-Policy header: Restrict the loading of malicious resources and specify the sources from which scripts and style sheets are allowed to be loaded. Validate server-side input: Validate input received from Ajax requests to prevent attackers from exploiting input vulnerabilities. Use secure Ajax libraries: Take advantage of automatic CSRF protection modules provided by libraries such as jQuery.
