Testing if a checkbox is checked with jQuery

Use .is(':checked') to determine whether or not it's checked, and then set your value accordingly.

More information here.

$("#ans").attr('checked') 

will tell you if it's checked. You can also use a second parameter true/false to check/uncheck the checkbox.

$("#ans").attr('checked', true);

Per comment, use prop instead of attr when available. E.g:

$("#ans").prop('checked')