How to change pseudo-class css style in jquery

In modern web development, JavaScript and jQuery have become one of the essential tools. Among them, jQuery's selectors and pseudo-classes are commonly used in web development. However, many people find that it is not possible to change CSS pseudo-class styles directly using jQuery. This article will introduce how to use jQuery to change pseudo-class CSS styles.

First, let’s briefly review CSS pseudo-classes. CSS pseudo-classes are used to control the style of HTML elements in specific states. For example, the :hover pseudo-class is used to add styles when the mouse is hovering over the element, the :active pseudo-class is used to add styles when the element is activated (such as being clicked), and the :focus pseudo-class is used to add styles when the element is selected (such as Add styles when using the tab key). In CSS, we can use pseudo-classes like this:

a:hover {
    color: red;
}

The above rules mean: when the mouse is hovering over the link element, change the color of the link text to red.

However, in jQuery, we cannot directly use the pseudo-class name to get the element. For example, the following code is invalid:

$("a:hover").css("color", "red");

This is because jQuery's selector engine can only handle CSS selectors, but not CSS pseudo-class selectors. Therefore, we need to use other methods to change pseudo-class CSS styles.

After some research and practice, we found that we can use jQuery's event processing function to simulate CSS pseudo-class effects. For example, we can write the following code:

$("a").hover(function(){
    $(this).css("color", "red");
}, function(){
    $(this).css("color", "");
});

The above code means: when the mouse hovers over the link element, change the color of the link text to red; when the mouse leaves the link element, change the color of the link text Restore to default value. In this way, we can achieve the style effect when the mouse is hovering.

Similarly, we can also simulate other CSS pseudo-class effects in jQuery. For example, the following code can simulate the :focus pseudo-class effect in CSS:

$("input").focus(function(){
    $(this).css("border-color", "blue");
}).blur(function(){
    $(this).css("border-color", "");
});

The above code means: when the input box is selected, change the border color to blue; when the input box loses focus, change the border color Colors are restored to default values. In this way, we can simulate the style effect when using the :focus pseudo-class.

In short, although CSS pseudo-class names cannot be used directly to change styles in jQuery, we can still achieve the same effect by simulating events. For some more complex CSS pseudo-classes, you may need to use more JavaScript code to implement, but it is not difficult to achieve. Through this method, we can use the power of jQuery and JavaScript to achieve customized web page effects.

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