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Restrictive analysis of events that cannot trigger bubbling behavior
- WBOYOriginal
- 2024-01-13 11:13:15872browse
Analysis of the limitations of bubbling events: What kind of events cannot trigger bubbling behavior?
Introduction:
DOM (Document Object Model) is the basic structure of web pages. Dynamic effects and interactions of web pages can be achieved by operating DOM. DOM events are an important mechanism in Javascript, used to respond to user operations or events triggered by the browser. Bubbling events are a special type of DOM events, which refer to the behavior of events bubbling up in the DOM tree. However, bubbling events have limitations, and some events cannot trigger bubbling behavior. This article will analyze the limitations of bubbling events in detail and demonstrate these scenarios through specific code examples.
1. Event types that do not trigger bubbling behavior:
- Focus event:
Focus event is triggered when the DOM element obtains focus and will not bubble to the parent element . For example, in the following code, if the input element is clicked, only the focus event of that element will be triggered, but will not bubble to its parent element div.
<div onclick="console.log('div clicked')">
<input type="text" onclick="console.log('input clicked')" />
</div>- Blur event:
The Blur event is triggered when the DOM element loses focus and will not bubble up to the parent element. The following is a sample code:
<div onclick="console.log('div clicked')">
<input type="text" onblur="console.log('input blurred')" />
</div>- Change event:
The Change event is triggered when the value of a DOM element changes, such as when an input box or drop-down list changes selection. However, the event does not bubble up to the parent element. The following is a code example:
<div onclick="console.log('div clicked')">
<input type="text" onchange="console.log('input changed')" />
</div>- Load event:
The Load event is triggered when the DOM element or the entire document is loaded, such as when the image is loaded or the page is loaded. The event also does not bubble up to parent elements. The following is a sample code:
<div onclick="console.log('div clicked')">
<img src="image.jpg" onload="console.log('image loaded')" / alt="Restrictive analysis of events that cannot trigger bubbling behavior" >
</div>- Unload event:
The Unload event is triggered when the entire document is unloaded or closed, and will not bubble to the parent element. The following is a code example:
<div onclick="console.log('div clicked')">
<body onunload="console.log('document unloaded')">
...
</body>
</div>2. Application scenarios of bubbling events:
Although bubbling events have limitations, there are still many application scenarios. For example, when clicking a button to trigger an event, you often need to process some related logic of the button's parent or ancestor elements. The following is a code example:
<div id="container" onclick="console.log('div clicked')">
<button onclick="console.log('button clicked')">Click me</button>
</div>In the above code, when the button is clicked, in addition to triggering the button's click event, it will also bubble up to the click event of the ancestor element div.
Conclusion:
Bubbling events are an important mechanism in DOM events, which can make events bubble up along the DOM tree to handle more flexible interaction logic. However, bubbling events are not supported by all event types. This article details some event types that do not trigger bubbling behavior and provides specific code examples. Understanding these limitations allows you to better apply bubbling events and avoid unnecessary trouble during the development process.
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