What is the purpose of the HTML “no-js” class?

Question

I notice that in a lot of template engines, in the HTML5 Boilerplate, in various frameworks and in plain php sites there is the no-js class added onto the

Answer 1

When Modernizr runs, it removes the "no-js" class and replaces it with "js". This is a way to apply different CSS rules depending on whether or not Javascript support is enabled.

See Modernizer's source code.