Learn the fundamentals of HTML, CSS, and JavaScript—the essential building blocks of any website—and how to use them in web scraping and data extraction.
Every web scraping project begins with a bit of detective work. While it’s easy for a human to visually identify the data on a webpage, a computer needs precise instructions to locate that same information. To give those instructions, we rely on three key components of a webpage: HTML, CSS, and JavaScript.
When you visit a website, the data necessary to display the page is delivered to your computer in a format called HTML (HyperText Markup Language). HTML contains the text, links, and images that make up the visible content of a webpage. If you want to extract data from a website, you need to direct your scraper to the exact location within the HTML where the data is stored.
For a deeper dive into HTML and its structure, we recommend checking out MDN's HTML documentation, a reliable and comprehensive resource.
CSS (Cascading Style Sheets) is responsible for styling the content of a webpage. It controls elements like layout, colors, fonts, and positioning, making the page visually appealing. While CSS primarily deals with a site’s appearance, it also plays a role in web scraping. You can use CSS selectors to pinpoint specific data within the HTML structure, making it a powerful tool for navigating a webpage’s layout.
To learn more about CSS and how to use selectors for data extraction, check out MDN’s CSS documentation.
While HTML and CSS provide the structure and style of a webpage, they remain static without JavaScript. JavaScript is what makes web pages interactive, allowing users to interact dynamically with the site. For web scraping, understanding JavaScript is crucial, especially for pages where data loads dynamically or relies on user interaction.
The great news is that you don’t need to be a seasoned programmer to grasp the basics of JavaScript, and you can even experiment directly in your browser. For a thorough introduction to JavaScript, head over to MDN’s JavaScript documentation.
Next, we’ll guide you through using your browser’s DevTools to inspect and interact with web pages, an essential step in learning how to extract data more efficiently.