HTML, as a markup language forming the backbone of basic web page design, had originally gone through several revisions rather quickly shortly after it was introduced in 1995. As of the turn of the millennium, however, the standard had settled in its "HTML 4" variation and remained in that level of development for roughly a decade and a half — but this was superseded by "HTML 5" as of several years ago. Among its many touted features is more direct support for having high-quality video and audio media played within the browser without as much need for separately downloading large media files. The HTML 5 standard is also what allows web pages to directly execute vector-based graphics through syntax that exists alongside the familiar tags.
A recent trend in contemporary web design that was enabled by the advent of HTML 5 is the use of parallax scrolling techniques to make certain background elements move more sharply than other background features while the viewer scrolls down the page. Through various web design software that supports manipulating SVG-based aesthetic elements, it is entirely plausible for a website's landing page to show sophisticated transformations as the page's scroll bar is moved down. Many years ago, this would have been accomplished either by structuring the entire website as an Adobe Flash file or by using the now-discontinued Adobe Edge software.