In-depth discussion of the working principle and practical application of jQuery listening method-JS Tutorial-php.cn

In-depth discussion of the working principle and practical application of jQuery listening method

王林

Release： 2024-02-24 20:09:06

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In-depth discussion of the working principle and practical application of jQuery listening method

jQuery is a JavaScript library widely used in web development. It simplifies the traversal, manipulation, event handling, and animation of HTML documents. Among them, the listening method is a very important part of jQuery, which can help us respond to user operations. This article will introduce the principles and applications of jQuery listening methods in detail, and give specific code examples.

1. The principle of jQuery listening method

In jQuery, the listening method is mainly implemented through the on() method, which binds to the specified selector element. Define one or more event handling functions. The principle of the listening method is based on the DOM event model, that is, event bubbling and event capturing. Event bubbling starts from a specific element and propagates upward to the root node of the document tree; event capture propagates downward from the root node of the document tree to specific elements.

The jQuery listening method uses this mechanism. When binding the event processing function, you can choose whether to use event bubbling or event capturing. Through the monitoring method, we can simply and efficiently implement monitoring and response to user operations.

2. Application of jQuery listening method

(1) Element click event monitoring

<!DOCTYPE html>
<html>
<head>
  <title>jQuery监听方法示例</title>
  <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
  <script>
    $(document).ready(function(){
      $("#btn").on("click", function(){
        alert("按钮被点击了！");
      });
    });
  </script>
</head>
<body>
  <button id="btn">点击我</button>
</body>
</html>

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In the above sample code, we use on() The method listens to the click event of the button. When the button is clicked, a prompt box pops up. This is one of the simplest applications of the listening method.

(2) Element mouse hover event monitoring

<!DOCTYPE html>
<html>
<head>
  <title>jQuery监听方法示例</title>
  <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
  <script>
    $(document).ready(function(){
      $("#hoverElement").on("mouseover", function(){
        $(this).css("color", "red");
      });

      $("#hoverElement").on("mouseout", function(){
        $(this).css("color", "black");
      });
    });
  </script>
</head>
<body>
  <p id="hoverElement">鼠标悬停在这里试试看</p>
</body>
</html>

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In this example, we listen to the mouse hover event and mouse move out event of the element, and realize that the text turns red when the mouse hovers. , the effect of the text returning to black when the mouse is moved out.

3. Conclusion

By understanding the principles and applications of jQuery listening methods, we can handle user operations more flexibly and improve the interactivity and user experience of web pages. In actual development, the listening method is one of the commonly used functions in jQuery. Being proficient in its principles and applications can help us better develop feature-rich Web pages.

We hope that the content introduced in this article can help readers better understand the jQuery monitoring method and apply it to actual projects in daily development. jQuery is a powerful, easy-to-learn and easy-to-use JavaScript library that is an indispensable tool for front-end developers.

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