THE PARTS
Code plus assets
MDN explains that websites are built mainly from HTML, CSS and JavaScript, plus assets such as images, music, video and PDFs.
Weigh the partsHOW A WEB PAGE WORKS
One page,
dozens of files.
A web page looks like one thing.
71 REQUESTS for the median desktop page in 2024
2,652 KB Median desktop page, October 2024
- HTML for structure
- CSS for looks
- JavaScript for action
- Plus the images that weigh the most
Behind it, your browser fetches an HTML file, style sheets, scripts, fonts and images, often from several servers, and assembles them in a moment. Here is what goes into a page, where the idea started and how heavy pages have become.
THE SHORT ANSWER
A page is a bundle
your browser builds.
The idea began at CERN in 1990.
Today's pages are far bigger.
THE JOURNEY
Address book, then delivery
Your browser asks DNS for the server's real address, sends an HTTP request, and the files arrive as small chunks called packets.
Follow the steps
THE FIRST PAGE
Live at CERN by Christmas 1990
The first browser, server and web page ran on a computer at CERN. info.cern.ch was the address of the world's first web server.
Read the historyA QUICK WEIGH-IN
What makes
a page heavy?
Pick a part of a page to see how much the median desktop page loaded of it in October 2024. The bar shows how much it adds to the page's weight.
Median figures from the HTTP Archive Web Almanac 2024 page weight chapter. Medians for each file type do not add up exactly to the median total.
WHAT HAPPENS WHEN YOU OPEN A PAGE
From address
to screen.
MDN, the web developer reference, describes the journey in a few steps.
Look up the address
The browser asks a DNS server for the real address of the server the website lives on.
Ask for the page
It sends an HTTP request to that server, asking for a copy of the website.
Receive the files
If the server agrees, it replies "200 OK" and sends the files in small chunks called packets, over TCP/IP.
Assemble and show
The browser puts the HTML, CSS, JavaScript and assets together into the page you see.
TWO NUMBERS WORTH KNOWING
Pages keep
putting on weight.
One figure on today's typical page,
one on how fast mobile pages grew.
2,652 KB
Median desktop page, October 2024
The median mobile page was 2,311 KB. In 2022 the figures were 2,312 KB on desktop and 2,037 KB on mobile.
PAGE WEIGHT · WEB ALMANAC 2024
357%
Growth of the median mobile page since 2014
The median mobile page grew from 505 KB in October 2014 to 2,311 KB in October 2024. The median desktop page grew by 120%.
TEN-YEAR GROWTH · WEB ALMANAC 2024
Weight is the total of the files a browser downloads for one page. The 2024 figures cover both home pages and inner pages.
WHERE PAGES BEGAN
One server,
one page, 1990.
CERN says that by Christmas 1990 the basic concepts of the web, HTML, HTTP and the URL, had been defined and the first browser/editor and server software written. The first web page gave information about the World Wide Web project itself.
On 30 April 1993 CERN put the World Wide Web software in the public domain, and released the next version with an open licence. CERN says these steps allowed the web to flourish. A restored copy of the first website is still online at info.cern.ch.
Questions
Questions people ask
What is a web page made of?
Mainly HTML, CSS and JavaScript code, plus assets such as images, video and documents, according to MDN. The browser downloads these files and assembles them into the page you see.
How big is a typical web page?
The HTTP Archive Web Almanac found the median desktop page weighed 2,652 KB in October 2024 and the median mobile page 2,311 KB.
How many files does a page load?
The median page made 71 requests on desktop and 66 on mobile in 2024, including 24 JavaScript files and 18 images on desktop.
What was the first web page?
CERN says the first web page, served from info.cern.ch by Christmas 1990, gave information about the World Wide Web project. A restored copy is still online.
What does "200 OK" mean?
It is the server's reply when it accepts a browser's request for a page. MDN describes it as the server saying yes before it sends the website's files.
Where the facts come from
Updated