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

If your use case is that you have a form (e.g., a login form) and your server-side script needs to know if the user has JavaScript enabled, you can do something like this:

This will change the value of js_enabled to 1 before submitting the form. If your server-side script gets a 0, no JS. If it gets a 1, JS!