The correct way to understand the pointing problem of this in jQuery

How to correctly understand the pointing problem of this in jQuery

In the process of learning to use jQuery, many beginners often encounter the pointing problem of this and confuse this The pointed object leads to unexpected results. Correctly understanding the pointer of this in jQuery is one of the keys to mastering jQuery programming. Only by clearly understanding the pointer of this can we write correct and efficient code. This article will help readers solve this problem through specific code examples.

In jQuery, the pointer of this is a common but easily confusing concept. During operations such as binding events, traversing elements, and calling methods, the pointing of this may change. Therefore, it is necessary to carefully study and understand the specific pointing of this in different scenarios.

1. This in the event handler points to

In jQuery, when we use an event handler to bind an event, this usually points to the element that triggered the event. For example, when a button is clicked, this in the event handler points to the button element, and various properties and methods of the button can be manipulated through this. The following is a simple sample code:

$("button").click(function(){
    $(this).text("按钮被点击了");
});

In this example, after clicking the button, the text of the button will be modified to "The button was clicked". This is because this points to the button element that triggered the click event.

2. This in traversing elements points to

In the process of traversing elements, this usually points to the element currently being operated on. With each method we can easily iterate through the elements and manipulate them. Here is a sample code:

$("li").each(function(){
    $(this).css("color", "red");
});

In this example, iterate through each li element and set their text to red. this points to the li element currently being traversed, and this element can be manipulated through this.

3. Use the this pointer in the jQuery method

When calling the jQuery method, the pointer of this depends on the implementation of the specific method. For example, when using the toggle method, this points to the clicked element. Here is a sample code:

$("button").toggle(function(){
    $(this).text("第一次点击");
}, function(){
    $(this).text("第二次点击");
});

In this example, after clicking the button, the text will alternately change to "First click" and "Second click". This inside the toggle method points to the clicked button element.

To sum up, the correct understanding of the pointing of this in jQuery needs to be judged according to the specific scenario. In an event handler, this usually points to the element that triggered the event; when traversing elements, this points to the element currently being operated on; when calling a jQuery method, the point of this depends on the implementation of the specific method. Through careful study and practice, you can become more proficient in the problem of pointing this and write efficient and correct jQuery code.

I hope this article can help readers correctly understand the pointing problem of this in jQuery and be handy in daily front-end development work. Any technology requires continuous practice and summary, come on!

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