However, most older web browsers either did not fully implement the specifications for these languages or were developed prior to the finalization of the specifications (Microsoft Internet Explorer version 5.0 for the Macintosh platform, released in 2000, was the first major web browser with full support for CSS Level 1, for example).
然而，多数旧的网页浏览器没有完全实施这些语言的定义或者在这些定义完成之前就已被开发（比如，Macintosh平台上的Microsoft Internet Explorer版本5.0发行于2000年，在主流网页浏览器中最早完全支持CSS Level 1）。