Browser

Detailed explanation

A browser fetches a page's HTML, CSS, and JavaScript and renders it into the interface a visitor actually sees and interacts with. Different browsers, and different versions and engines such as Chromium, WebKit, and Gecko, can render layout, fonts, and interactive elements slightly differently, which is why cross-browser testing remains part of any serious QA process before a site launch or redesign.

For marketing and analytics, browser choice also affects tracking: browsers like Safari and Firefox apply stricter default rules around third-party cookies and tracking scripts than Chrome has historically, which changes how conversion tracking, retargeting, and attribution behave depending on which browser a visitor uses. Analytics tools typically report browser breakdowns precisely so teams can catch a rendering or tracking issue that is isolated to one browser rather than affecting the whole site.

For “what is a browser” or “why does my site look different in Safari” searches, this entry is a starting point. See CMS for the software that generates the code a browser renders, and SSL for a security layer browsers actively check before loading a page.