How to create an on/off switch with Javascript/CSS?

Question

I want to have a sliding switch. On the left would be Off and on the right would be On. When the user toggles the switch, I want the \'slider\' portion to slide to the other

Answer 1

Initial answer from 2013

If you don't mind something related to Bootstrap, an excellent (unofficial) Bootstrap Switch is available.

It uses radio types or checkboxes as switches. A type attribute has been added since V.1.8.

Source code is available on Github.

Note from 2018

I would not recommend to use those kind of old Switch buttons now, as they always seemed to suffer of usability issues as pointed by many people.

Please consider having a look at modern Switches like those.