Web Development

What is HTML / CSS / JavaScript?

HTML, CSS, and JavaScript are the three fundamental technologies that every website is built on — structure, style, and interactivity.

Definition

HTML or HyperText Markup Language, CSS or Cascading Style Sheets, and JavaScript are the three fundamental technologies that every website is built on. HTML provides the structure, the headings, paragraphs, images, and links that make up a page's content. CSS controls the visual appearance, colors, fonts, layout, and spacing. JavaScript adds interactivity and dynamic behavior, dropdown menus, form validation, animations, and more.

Why It Matters for Small Businesses

You do not need to become a developer, but understanding what these technologies do helps you communicate more clearly with developers, evaluate the quality of work being done on your site, and make more informed decisions about website projects. Knowing the basics also helps you spot when something is technically wrong or unnecessarily complicated.

Example

A small business owner reviews their website speed report and sees render-blocking JavaScript flagged as an issue. Understanding that JavaScript is the code layer responsible for interactive features, they can ask their developer a specific question: which scripts are blocking page rendering and can they be deferred or removed. This is a far more productive conversation than just saying the site is slow.

Related Terms

Page SpeedJavaScript and CSS can both be sources of performance issues

Core Web VitalsJavaScript execution is a common factor in poor INP scores

Responsive DesignCSS is the technology that makes responsive design work

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