//using plane javascript
if(document.getElementById('on_or_off_checkbox').checked) {
//I am checked
}
//using jQuery
if($('#on_or_off_checkbox').is(':checked')){
//I am checked
}if ($('#check_id').is(":checked"))
{
// it is checked
}$(".checkbox").change(function() {
if(this.checked) {
//Do stuff
}
});
$( "SELECTOR" ).attr( "checked" ) // Returns ‘true’ if present on the element, returns undefined if not present
$( "SELECTOR" ).prop( "checked" ) // Returns true if checked, false if unchecked.
$( "SELECTOR" ).is( ":checked" ) // Returns true if checked, false if unchecked.if (!$("#checkboxID").is(":checked")) {
// do something if the checkbox is NOT checked
}$('input.checkbox').is(':checked')