How to fix the header in jquery

jQuery is a widely used JavaScript library that makes dynamic manipulation of web pages easier. Tables are a common component in many web applications. However, when the table is too long, users may need to scroll to view the content, and the header disappears from the top of the screen. To make the table easier to use, you can use jQuery to pin the header to the top of the screen so it is always visible. In this article, we will introduce how to use jQuery to fix the header.

1. Prepare the table

First, you need to prepare an HTML document containing the table. Here is a simple example form:

Name	Telephone	e-mail
张三	1234567890	zhangsan@example.com
李四	0987654321	lisi@example.com
王五	4567891230	wangwu@example.com

2. Add CSS Styles

Next, you'll need to add some CSS styles to make the table look and behave like your website or application. You can use the following styles as a starting point and then modify them as needed:

table {
width: 100%;
border-collapse: collapse;
}

th , td {
padding: 8px;
text-align: left;
border-bottom: 1px solid #ddd;
}

th {
background-color: #f2f2f2;
}

tbody {
height: 300px;
overflow-y: scroll;
display: block;
}

3. Get the header

In order to fix the header, you need to first get the reference to the header. You can get the table header using the following code:

var $table = $('table');
var $thead = $table.find('thead');
var $th = $thead.find('th');

4. Get the table body

Next, you need to get a reference to the table body. In order to keep the table header and table body aligned, you need to make the table body scrollable and display it as a block-level element. You can get the table body using the following code:

var $tbody = $table.find('tbody');
$tbody.css('display', 'block');
$ tbody.css('height', '300px');
$tbody.css('overflow-y', 'scroll');

5. Create a new table

Now you need to create a new table to contain the header and body obtained previously. You can create a new table using the following code:

var $new_table = $('

');
var $new_thead = $('');
$ new_table.append($new_thead);
var $new_tr = $('');
$new_thead.append($new_tr);

6. Copy the header unit Cells

Next, you need to copy each cell in the table header and add it to the first row of the new table. You can do this using the following code:

$th.each(function() {
var $clone = $(this).clone();
$new_tr.append($clone );
});

7. Insert the new table into the DOM

Finally, you need to insert the new table into the DOM before the original table. You can do this using the following code:

$new_table.insertBefore($table);

8. Fixed table header

Now you have created Create a new table with a fixed header and insert it into the DOM. However, when the user scrolls the screen, the header still scrolls out of view. To fix the header, you can adjust the header's position based on the scroll offset when a scroll event occurs. You can use the following code to achieve this functionality:

$(window).scroll(function() {
var scroll_top = $(this).scrollTop();
var table_top = $table. offset().top;
if (scroll_top > table_top) {

$thead.css('position', 'fixed');
$thead.css('top', 0);

} else {

$thead.css('position', 'static');
$thead.css('top', '');

}
});

This code Will be triggered when the window is scrolled, and set the header position to fixed or static based on the offset of the scroll. If the scroll offset is greater than the offset at the top of the table, set the header to fixed. Otherwise, set the header to static.

At this point, you have successfully fixed the header. As the user scrolls, the header will remain at the top of the screen and move with the scroll. With this simple tip, you can easily enhance the usability and accessibility of your web application.

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