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Computer Science IGCSEPDF 56
142 pagesrevision 46930
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4. Web Browsers
A
fromtheInternet.
is a software application used to access and display webpages
web browser
Examples: Google Chrome, Mozilla Firefox, Microsoft Edge, Safari.
Main functions:
o Connects to websites via HTTP(S) protocols.
o Translates HTML code and displays formatted webpages.
o Supports security through SSL/TLS.
o Provides features such as bookmarks, browsing history, ad-blockers, and
privacy settings.
5. Retrieval and Display of Webpages
1. The user enters a URL into the browser.
2. The browser contacts a DNS (Domain Name System) server to translate the
domain name into an IP address.
3. The DNS returns the matching IP address (if it exists).
4. The browser sends a request to that IP (web server).
5. The web server responds by sending the requested webpage’s HTML.
6. The browser interprets and displays the webpage content to the user.
6. Cookies
Cookies
are small text files stored on the user’s computer by websites.
They store user preferences, login details, and browsing activity.
Used for:
o Auto-filling forms
o Personalizing website experience
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