Web Standards maximizes cross browser compatibility and ensure your website will be visible on all platforms. These standards help maintain a uniform code and design.
Choosing the proper HTML version is important when creating a portfolio page. HTML5 is not fully standardized today, however you should use it for your portfolio, to show off your design and coding skills.
Metadata is data embedded in your HTML page which includes information about your website. Metadata can be used for SEO and to give more information about your website.
CSS (Cascading Style Sheets), are used to help style and format HTML pages. There are many different versions, but CSS3 is the current version and should be used for your website to keep it updated. A separate CSS sheet should be used, so that if one change is made, it will change all the pages that have this CSS linked. CSS, like HTML can be validated with many different websites.
Making your page accessible to visually impaired people is very important to web standards. A good way to do this is by using the alt attribute. These attributes are a textual description of what they would be seeing on the page. For instance when your page is being accessed by a screen reader, it will tell the person what they are accessing. Here is an example of how this is implemented.