select box checked or not jquery code example

Example 1: How to check whether a checkbox is checked in jQuery?

//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
}

Example 2: check whether a checkbox is checked in jQuery

if ($('#grepperRocks').is(':checked')) {
	// this checkbox is checked
}