With the advent of CSS3 there are many new ways to style web pages. One of the new features in CSS3 is the ability to change the highlighting color on web pages using CSS. It seems that many websites ignore this simple to implement feature. By default the color will be inherited by your operating system colors. On Windows Vista the hex. color is #3399ff.

Here's How To Change The Text Selection Color:

::selection { background: red; color: white; } ::-moz-selection { background: red; color: white; }

Notes:

This is currently supported by Firefox and Safari. I would suspect that Opera also supports it. Unfortunately Internet Explorer does not support it, but with IE8 coming out soon supporting CSS better, it may work in there as well.

Sources