Cross-browser refers to the ability for a website, web application, HTML construct or client-side script to function correctly across all, or the majority of web browsers.

The term cross-browser is often confused with multi-browser. Multi-browser is a new paradigm in web development that allows a website or web application to provide more functionality over several web browsers, while ensuring that the website or web application is accessible to the largest possible audience without any loss in performance.

Cross-browser capability allows a website or web application to be properly rendered by all browsers.

The term cross-browser has existed since web development began.

The term is still in use, but to lesser extent. The main reasons for this are:

  • Later versions of both Internet Explorer and Netscape included support for HTML 4.0 and CSS1, proprietary extensions were no longer required to accomplish many commonly desired designs.
  • Somewhat more compatible DOM manipulation techniques became the preferred method for writing client-side scripts.
  • The browser market has broadened, and to claim cross-browser compatibility, the website is nowadays expected to support browsers such as Mozilla FirefoxOperaGoogle Chrome and Safari in addition to Internet Explorerand Netscape.
  • There has been an attitude shift towards more compatibility in general. Thus, some degree of cross-browser support is expected and only its absence needs to be noted.

Source