In Vue, the core difference between v-if and v-show is the rendering method and applicable scenarios. v-if is "true deletion". When the condition is false, the element will not be rendered to the DOM. It is suitable for scenes that are not frequently switched, such as content that does not need to be displayed during initialization; v-show is "fake hiding", and displays through CSS, the element always exists in the DOM, which is suitable for scenes that are frequently switched, such as pop-up windows or drop-down menus. The key differences between the two are reflected in: 1. Different rendering methods; 2. Different switching overhead; 3. Different initial rendering overhead; 4. Whether to retain state. Use suggestions include: use v-if for form verification prompts, use v-show for frequently switching content, and use complex components to optimize performance.

In Vue, it is a common requirement to control whether an element is displayed. Vue provides two common ways: v-if and v-show . They can all implement conditional rendering, but the applicable scenarios are different. Understanding their differences can help you write more efficient and reasonable code.

v-if is "real deletion", suitable for scenarios that do not switch frequently

v-if is characterized by lazy rendering . When the condition is false, the element will not appear in the DOM, which is equivalent to "removing" directly from the page. The corresponding element is created and inserted only when the condition becomes true.

This is logically much like "create if the condition is true", so it applies to:

• Content that may not be displayed when the page is initialized
• Modules with infrequent changes in conditions, such as panels that are displayed after the user logs in

For example:

 <div v-if="isLoggedIn">Welcome back! </div>

If isLoggedIn is false, this div does not exist in the DOM at all. This is helpful in reducing unnecessary DOM nodes, especially when the component level is deep or the content is high.

Note: If you need to control the display of multiple elements at the same time, you can wrap them with <template v-if> so that no additional DOM nodes are introduced.

v-show is "fake hiding", suitable for frequent switching scenarios

Unlike v-if , v-show only controls the visibility of elements through CSS display: none . Regardless of the conditions, the element is always retained in the DOM, just whether it is displayed or not.

It's more like a "switch":

 <div v-show="isVisible">I can switch it repeatedly</div>

As long as isVisible changes, Vue will switch the display status of the element. This method is more suitable for:

• UI elements that need to be frequently switched (such as pop-up windows, drop-down menus)
• The rendering has been completed, and you only need to control whether the display is displayed in the future.

Because there is no process of destruction and reconstruction, the performance overhead is much smaller than that v-if .

Key Differences between v-if and v-show

Simply put:

• If you want a module not to load at the beginning , or rarely switch states , it is more appropriate to use v-if .
• If you want a module to quickly switch the display status , use v-show to be more efficient.

Practical usage suggestions

• Form verification tips : v-if is usually used because this information often appears under specific conditions.
• Tab switching content : If it is static content, you can use v-show ; if each tab content is complex and does not switch frequently, you can use v-if to reduce the DOM burden.
• Animation transition effect : When used in conjunction with <transition> , v-if is more suitable because it is the real "in and out" process.

There are also times when you can use it in combination:

 <template v-if="showTab">
  <div v-show="activeTab === &#39;home&#39;">Home page content</div>
  <div v-show="activeTab === &#39;profile&#39;">Profile</div>
</template>

The benefits of doing this are:

• Outer layer determines whether to load a tab group (save resources)
• Use v-show internally to quickly switch the current tab content

Basically that's it. Understand the core differences between v-if and v-show , and then choose according to actual needs, you can write a more suitable Vue template.

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