how to make a checkbox checked in javascript 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: javascript check uncheck checkbox

document.getElementById("myCheckBoxID").checked = true; // Check
document.getElementById("myCheckBoxID").checked = false;// Uncheck

Example 3: fill checkbox javascript

// Check
document.getElementById("checkbox").checked = true;

// Uncheck
document.getElementById("checkbox").checked = false;