CSS three digit hex colors

Some might consider this a micro-optimization, and there are many tools that can do this automatically at runtime, but there is often a need for developers to apply in source code and/or understand the output of automated tools.

A hexadecimal color is specified with: #RRGGBB, where the RR (red), GG (green) and BB (blue) hexadecimal integers specify the components of the color.

Some common colors that most are familiar with:

CSS color name 6 digit hex 3 digit hex
white #ffffff #fff
red #ff0000 #f00
blue #0000ff #00f
black #000000 #000

Some more complex examples:

6 digit hex 3 digit hex
#112233 #123
#aabbcc #abc
#cccccc #ccc

NOTE: while you are at these changes, this would also be a good time to change to all lower-case to improve the compression algorithms.

REFERENCES:

RIP Yahoo Site Explorer –

I recently was reviewing a customer website and found this markup, while it looked vaguely familiar, I had do do a little searching to find it’s original use.

<meta name=“y_key” content=“xxxxxx” />

This was for Yahoo Site Explorer, it existed for a little over six years, from September 2005 until November 2011!

It provided a lot of similar functions as the Google Search Console.??https://en.wikipedia.org/wiki/Yahoo_Site_Explorer

TLDR; If you find this markup in any website, it’s relatively safe to assume that you can remove it with very little impact other than some saved bytes in your network traffic.

X-Robots-Tag HTTP Response Header

Sometimes, the use of robots.txt is just not enough to prevent Google and other search engines from indexing a URL.

I’ve encountered situations where ‘redirects’ were indexed, in these cases, it is often helpful to target the problem endpoint with the following HTTP Response Header.

X-Robots-Tag: noindex