In website development, using a common header and footer provides a consistent look and navigation structure for each page.

In website development, using a common header and footer provides a consistent look and navigation structure for each page. Doing so reduces duplication of code and simplifies maintenance. In JavaScript, we can achieve this by using modularity.

Modularization is a development method that splits code into independent modules. In this case, we can create a header module and a bottom module and then reference them in every page. The following is an example implementation process:

First, create a header.jsJavaScript file called that defines the content of the header module. In this file, you can write the HTML structure and styling of the header, as well as any JavaScript logic related to the header. For example:

// header.js

const header = document.createElement('header');
header.innerHTML = '<h1>网站标题</h1><nav>&l