Analysis of the meaning of this when binding click events in jQuery-JS Tutorial-php.cn

Analysis of the meaning of this when binding click events in jQuery

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Release： 2024-02-28 22:03:03

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Analysis of the meaning of this when binding click events in jQuery

When using jQuery to bind events, we often encounter problems with the use of this keyword. The meaning of this in jQuery is slightly different from that in native JavaScript. It points to the DOM element that currently triggers the event. In this article, we will use specific code examples to analyze the meaning of this when binding click events in jQuery.

Suppose we have a simple HTML structure that contains a button and a paragraph element:

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Analysis of the meaning of this when binding click events in jQuery</title>
<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
</head>
<body>
<button id="myButton">点击我</button>
<p>这是一个段萼元素</p>
</body>
</html>

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Next, we use jQuery to bind the click event to the button, and in the event handler function The meaning of this output in:

$(document).ready(function(){
  $("#myButton").click(function(){
    console.log(this);
    console.log($(this).text());
  });
});

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In the above code, we selected the button element with the id "myButton" through the selector, and used the click method to bind the click event to the button. In the event handler function, we output the value of this and the text content of the button element through console.log.

When we click the button, we can see the output in the browser's developer tools:

<button id="myButton">点击我</button>
点击我

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This indicates that the this keyword points to the DOM element that currently triggers the event, which is the button element itself. Therefore, through this keyword we can directly operate the currently clicked element without the need for additional selectors.

In addition, if you need to obtain relevant information about the current event, such as obtaining the event source object, event type, etc., you can use the event object to obtain:

$(document).ready(function(){
  $("#myButton").click(function(event){
    console.log(event.target);
    console.log(event.type);
  });
});

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In the above code, we will The object event is passed into the event processing function as a parameter, the event source object is obtained through event.target, and the event type is obtained through event.type.

In summary, through the above example code, you can clearly see the meaning of this when binding a click event in jQuery. The this keyword in jQuery points to the DOM element that currently triggers the event, which can easily operate on the currently clicked element. At the same time, event-related information can also be obtained through the event object, thereby handling events more flexibly. I hope readers can better understand the use of this in jQuery through the analysis of this article.

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