The MDN HTML section talks about html being the building blocks for the web. This page goes over the use of hyperlinks and how html is used to annotate things like images, text, links, and more. This page also talks about how html works as it focuses heavily on the use of tags to divide and change sections of a webpage. This website contains the different elements (tags) that are used in html alongside other attributes that can be used to make your page look presentable to the public.
This page talks about CSS which is the stylesheet aspect of a webpage. These can be attatched to an HTML/XML webpage and they allow you to use the tags to customize the page such as making a link a different color or changing the font. There are many great refrences on this website for CSS including types, functions, pseudo-classes, and more that can be used to customize your page to make it look as professional as possible.
With this webpage I learned more about how DOM is used as it talks about DOM representing the structure of a document. This page does a great job at talking about how DOM is used including allowing different coding languages to change the page dynamically. This makes the webpage more interactive for the user and there are a lot of great tools on MDN to help you including the different interfaces you can use to do so.
This webpage discusses the functionality of JavaScript as a scripting-language for webpages it can also be used in non-browser enviornments. One thing you can do with JavaScript is change how your webpage behaves as JavaScript can act as the functionality part of the page in a similar way to how CSS is the customization of the page. The refrences here are also great as it goes over expressions such as assignments like += and how you can use statements like if...else to determine when something should happen on the webpage.
Overall, all of these things can be used to greatly improve your webpage as a good webpage should have an HTML, CSS, DOM, and JavaScript file. I also learned more about each of these and their capabilities and why it is important to use each one, especially DOM and JavaScript since I am pretty new to both of them. As well, I think MDN is a great website of all web coders as it is a clean website that's easy to use with lots of information on things that you can use to improve your webpage.