这些解决方案都不适合我的需要。我在寻找更像php的东西。在我看来，这个解决方案非常简单有效。

include.js - - - >

void function(script) {
    const { searchParams } = new URL(script.src);
    fetch(searchParams.get('src')).then(r => r.text()).then(content => {
        script.outerHTML = content;
    });
}(document.currentScript);

index . html - - - >

<script src="/include.js?src=/header.html">
<main>
    Hello World!
</main>
<script src="/include.js?src=/footer.html">

可以做一些简单的调整来创建include_once、require和require_once，它们可能都很有用，这取决于您正在做什么。下面是一个简短的例子。

include_once - - - >

var includedCache = includedCache || new Set();
void function(script) {
    const { searchParams } = new URL(script.src);
    const filePath = searchParams.get('src');
    if (!includedCache.has(filePath)) {
        fetch(filePath).then(r => r.text()).then(content => {
            includedCache.add(filePath);
            script.outerHTML = content;
        });
    }
}(document.currentScript);

希望能有所帮助!

一个简单的服务器端包含指令，包括在同一文件夹中找到的另一个文件，如下所示:

<!--#include virtual="a.html" --> 

你也可以试试:

<!--#include file="a.html" -->

html5rocks.com has a very good tutorial on this stuff, and this might be a little late, but I myself didn't know this existed. w3schools also has a way to do this using their new library called w3.js. The thing is, this requires the use of a web server and and HTTPRequest object. You can't actually load these locally and test them on your machine. What you can do though, is use polyfills provided on the html5rocks link at the top, or follow their tutorial. With a little JS magic, you can do something like this:

 var link = document.createElement('link');
 if('import' in link){
     //Run import code
     link.setAttribute('rel','import');
     link.setAttribute('href',importPath);
     document.getElementsByTagName('head')[0].appendChild(link);
     //Create a phantom element to append the import document text to
     link = document.querySelector('link[rel="import"]');
     var docText = document.createElement('div');
     docText.innerHTML = link.import;
     element.appendChild(docText.cloneNode(true));
 } else {
     //Imports aren't supported, so call polyfill
     importPolyfill(importPath);
 }

This will make the link (Can change to be the wanted link element if already set), set the import (unless you already have it), and then append it. It will then from there take that and parse the file in HTML, and then append it to the desired element under a div. This can all be changed to fit your needs from the appending element to the link you are using. I hope this helped, it may irrelevant now if newer, faster ways have come out without using libraries and frameworks such as jQuery or W3.js.

UPDATE:这将抛出一个错误，表示本地导入已被CORS策略阻塞。可能需要访问深层网络才能使用它，因为深层网络的特性。(意思是没有实际用途)

您可以使用HTML Imports的填充(https://www.html5rocks.com/en/tutorials/webcomponents/imports/)或简化的解决方案 https://github.com/dsheiko/html-import

例如，在你导入HTML块的页面上:

<link rel="html-import" href="./some-path/block.html" >

该块可以有自己的导入:

<link rel="html-import" href="./some-other-path/other-block.html" >

导入器用加载的HTML替换指令，就像SSI一样

这些指令将在你加载这个小JavaScript时自动提供:

<script async src="./src/html-import.js"></script>

它将在DOM准备就绪时自动处理导入。此外，它还公开了一个API，您可以使用该API手动运行、获取日志等等。享受:)

下面是我使用Fetch API和async函数的方法

<div class="js-component" data-name="header" data-ext="html"></div>
<div class="js-component" data-name="footer" data-ext="html"></div>

<script>
    const components = document.querySelectorAll('.js-component')

    const loadComponent = async c => {
        const { name, ext } = c.dataset
        const response = await fetch(`${name}.${ext}`)
        const html = await response.text()
        c.innerHTML = html
    }

    [...components].forEach(loadComponent)
</script>

不需要脚本。不需要做任何花哨的东西服务器端(尽管这可能是一个更好的选择)

<iframe src="/path/to/file.html" seamless></iframe>

由于旧的浏览器不支持无缝，你应该添加一些css来修复它:

iframe[seamless] {
    border: none;
}

请记住，对于不支持无缝链接的浏览器，如果您单击iframe中的链接，它将使框架指向该url，而不是整个窗口。一种解决方法是让所有链接都有target="_parent"，尽管浏览器的支持是“足够好”。