# Preload, Prefetech,DNS Prefetching

## Preload

`<link rel="preload">` 是一种 resource hint，用来指定页面加载后很快会被用到的资源，所以在页面加载的过程中，我们希望在浏览器开始主体渲染之前尽早 preload。

## Prefetch

`<link rel="prefetch">` 是一种 resource hint，用来告诉浏览器在页面加载完成后，利用空闲时间提前获取用户未来可能会访问的内容。

## DNS Prefetching

DNS prefetching 允许浏览器在用户浏览页面时在后台运行 DNS 的解析。如此一来，DNS 的解析在用户点击一个链接时已经完成，所以可以减少延迟。

```
<link rel=“dns-prefetch” href="//www.google-analytics.com">
```


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://mm.ricky.moe/network/liu-lan-qi/preload-prefetech-dns-prefetching.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.