Consistent navigation box for every page? (HTML) - html

Question

I've been working on making a personal site with a navigation bar. I read w3schools' article and used the code there to make my nav. There are some problems with this, however:
The same code needs to be copied and pasted on each page.
If I decide to add a new page, I have to add the navigation bar to the new page and add the new page's link to the navigation bar on every page.
If I find an error in the nav code, I have to fix it on each individual page.
Here's the code:
html {
color: blue;
font-family: sans-serif;
}
.resource-dropdown {
position: sticky;
display: inline-block;
}
.resource-dropdown-content {
display: none;
position: absolute;
background-color: #b51d1d;
min-width: 160px;
box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
padding: 12px 16px;
z-index: 1;
}
.resource-dropdown:hover .resource-dropdown-content {
display: block;
}
.resource-dropdown-content:hover {
color: greenyellow;
}
.topnav {
background-color: black;
}
.topnav a {
float: left;
color: #f2f2f2;
text-align: center;
padding: 14px 16px;
text-decoration: none;
font-size: 17px;
}
.topnav a:hover {
background-color: white;
color: black;
}
<div class="topnav">
Home
<div class="resource-dropdown">
<span><a>Resources</a></span>
<div class="resource-dropdown-content">
<p>Sites</p>
<p>Books</p>
<p>Videos</p>
<p>Other</p>
</div>
</div>
About
</div>
Is there a way to make a shortcut? (Something like the alias command in the C languages)

Answer 1

There is no shortcut in HTML only. If you avec a local server such as MAMP / XAMP for exemple, and that you're ready to make a bit of PHP, you'll be able to create one file for the menu, and include it in all other files. This way, each time you change the menu in the menu file, it'll change on every pages.
here is the official documentation on php include function : http://php.net/manual/en/function.include.php
here is the documentation of MAMP : https://www.mamp.info/en/#controlcenter