Add glossary pages for <blink> and HTML color codes

files/en-us/glossary/blink_element/index.md

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+---
+title: blink element (<blink> tag)
+slug: Glossary/blink_element
+page-type: glossary-definition
+---
+
+{{GlossarySidebar}}
+
+The **`<blink>` element** (blink tag) is an obsolete HTML feature no longer supported by web browsers, and no longer documented on MDN. It was used make text content blink on and off (flash) continually.
+
+## Brief history
+
+In the early days of the web (the early- to mid-90s), there were not many features available for styling web pages. The [CSS](/en-US/docs/Web/CSS) specification (version 1) was first released in 1996, and not adopted consistently by browsers until much later. Before CSS, browsers experimented with several features to make particular text sections stand out and grab the user's attention if desired. The `<blink>` element was one of these, introduced in early versions of [Netscape Navigator](/en-US/docs/Glossary/Netscape_Navigator); [Internet Explorer's](/en-US/docs/Glossary/Microsoft_Internet_Explorer) {{htmlelement("marquee")}} element was another one.
+
+The `<blink>` element was apparently created after a conversation in a bar in Mountain View between Netscape engineer [Lou Montulli](https://en.wikipedia.org/wiki/Lou_Montulli) and colleagues. When he went into the office the next morning, he found that one of his fellow engineers have stayed up all night and implemented it ([read the story here](https://web.archive.org/web/20220331020029/http://www.montulli.org/theoriginofthe%3Cblink%3Etag)).
+
+While initially popular, `<blink>` became much maligned because of overuse; many people found it annoying. More importantly, it degrades readability, and can be particularly problematic for users with visual impairments or [cognitive disorders](/en-US/docs/Web/Accessibility/Cognitive_accessibility) such as epilepsy or ADHD. It can be disorienting or, in the worst cases, even trigger seizures.
+
+The [Web Content Accessibility Guidelines](/en-US/docs/Glossary/WCAG) state that content that blinks, flashes, or moves should be pausable/stoppable/hidable (see [2.2.2: Pause, Stop, Hide](https://www.w3.org/WAI/WCAG21/Understanding/pause-stop-hide)), and further highlights the dangers of flashing content in [2.3.1: Three Flashes or Below Threshold](https://www.w3.org/WAI/WCAG21/Understanding/three-flashes-or-below-threshold).
+
+`<blink>` was never properly specified, and never achieved significant cross-browser support. It can be considered a piece of web history.
+
+## Syntax
+
+The `<blink>` element was used like this:
+
+```html example-bad
+<blink>In ancient browsers, I may have blinked</blink>
+```
+
+### Alternatives
+
+- The CSS {{cssxref("text-decoration-line")}} property has a `blink` value that should have the same effect, but most modern browsers ignore it.
+- The JavaScript {{jsxref("String.blink()")}} method wraps a text string in `<blink></blink>` tags but, as discussed earlier, this element is no longer supported anywhere.
+- [CSS animations](/en-US/docs/Web/CSS/CSS_animations) could still be used to create blinking text. However, you should avoid blinking text on web pages for the reasons discussed above.
+
+## See also
+
+- [Blink element](https://en.wikipedia.org/wiki/Blink_element) on Wikipedia

files/en-us/glossary/html_color_codes/index.md

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+---
+title: HTML color codes
+slug: Glossary/html_color_codes
+page-type: glossary-definition
+---
+
+{{GlossarySidebar}}
+
+**HTML color codes** is a _defacto_ general term used to describe the earliest-available methods for specifying colors on web pages. This includes HTML color names such as `black`, `purple`, and `aqua`, and hexadecimal notations such as `#000000`, `#800080`, and `#00ffff`. These were originally defined in HTML specifications — see for example the [HTML 3.2 color definitions](https://www.w3.org/TR/2018/SPSD-html32-20180315/#colors) of the original 16 HTML colors.
+
+It is no longer accurate to refer to colors on the web as "HTML color codes" or "HTML color names". Colors are now specified in the [CSS color module](/en-US/docs/Web/CSS/CSS_colors), and generally known as CSS colors or web colors.
+
+To look up web colors on MDN, see our {{cssxref("<color>")}} values reference documentation, or more specifically:
+
+- Color names: {{cssxref("<named-color>")}}.
+- Hexadecimal notations: {{cssxref("<hex-color>")}}.
+- Color functions:
+  - [sRGB](https://en.wikipedia.org/wiki/SRGB) color space: {{CSSXref("color_value/hsl", "hsl()")}}, {{CSSXref("color_value/hwb", "hwb()")}}, and {{CSSXref("color_value/rgb", "rgb()")}}.
+  - [CIELAB](https://en.wikipedia.org/wiki/CIELAB_color_space) color space: {{CSSXref("color_value/lab", "lab()")}} and {{CSSXref("color_value/lch", "lch()")}}.
+  - [Oklab](https://bottosson.github.io/posts/oklab/) color space: {{CSSXref("color_value/oklab", "oklab()")}} and {{CSSXref("color_value/oklch", "oklch()")}}.
+  - Other color spaces: {{CSSXref("color_value/color", "color()")}}.
+
+## See also
+
+- [Web colors](https://en.wikipedia.org/wiki/Web_colors) on Wikipedia