Blink element

The blink element is a non-standard presentational HTML element that indicates to a user agent (generally a web browser) that the page author intends the content of the element to blink (that is, alternate between being visible and invisible). The element was introduced in Netscape Navigator but is no longer supported by any modern Web browser; some, such as Internet Explorer, never supported the element at all.

Despite its initial popularity among home users in the 1990s, it has since fallen out of favor due to its overuse and the difficulty it presents in reading. The tag achieved notoriety for being user-unfriendly in the opinion of many designers.Lou Montulli, often credited as the inventor of the blink element, has said that he considers "the blink tag to be the worst thing I've ever done for the Internet", although he claims he only suggested the idea, without writing any actual code.

... At some point in the evening I mentioned that it was sad that Lynx was not going to be able to display many of the HTML extensions that we were proposing, I also pointed out that the only text style that Lynx could exploit given its environment was blinking text. We had a pretty good laugh at the thought of blinking text, and talked about blinking this and that and how absurd the whole thing would be. [...] Saturday morning rolled around and I headed into the office only to find what else but, blinking text. It was on the screen blinking in all its glory, and in the browser. How could this be, you might ask? It turns out that one of the engineers liked my idea so much that he left the bar sometime past midnight, returned to the office and implemented the blink tag overnight. He was still there in the morning and quite proud of it.

The blink element is non-standard, and as such there is no authoritative specification of its syntax or semantics. While Bert Bos of the World Wide Web Consortium has produced a Document Type Definition that includes syntax for the blink element (defining it as a phrase element on a par with elements for emphasis and citations), the comments in the DTD explain that it is intended as a joke.

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