How to detect if JavaScript is disabled?

Question

There was a post this morning asking about how many people disable JavaScript. Then I began to wonder what techniques might be used to determine if the user has it disabled.

Answer 1

In some cases, doing it backwards could be sufficient. Add a class using javascript:

// Jquery
$('body').addClass('js-enabled');

/* CSS */
.menu-mobile {display:none;}
body.js-enabled .menu-mobile {display:block;}

This could create maintenance issues on anything complex, but it's a simple fix for some things. Rather than trying to detect when it's not loaded, just style according to when it is loaded.