1//using plane javascript
2if(document.getElementById('on_or_off_checkbox').checked) {
3 //I am checked
4}
5
6//using jQuery
7if($('#on_or_off_checkbox').is(':checked')){
8 //I am checked
9}
1$('.myCheckbox').prop('checked', true);
2$('.myCheckbox').prop('checked', false);
1$( "SELECTOR" ).attr( "checked" ) // Returns ‘true’ if present on the element, returns undefined if not present
2$( "SELECTOR" ).prop( "checked" ) // Returns true if checked, false if unchecked.
3$( "SELECTOR" ).is( ":checked" ) // Returns true if checked, false if unchecked.
1// jQuery version 1.6 or above use:
2$("#myRadioID").prop("checked", true);
3
4//jQuery versions below 1.6 use:
5$("#myRadioID").attr('checked', 'checked');