Check/Uncheck checkbox with JavaScript (jQuery or vanilla)?

Question

How can a checkbox be checked/unchecked using JavaScript, jQuery or vanilla?

Answer 1

I would like to note, that setting the 'checked' attribute to a non-empty string leads to a checked box.

So if you set the 'checked' attribute to "false", the checkbox will be checked. I had to set the value to the empty string, null or the boolean value false in order to make sure the checkbox was not checked.