javascript checkbox all if checked code example

Example 1: get the state of a checkbox

function checkAddress()
{
    var chkBox = document.getElementById('checkAddress');
    if (chkBox.checked)
    {
        // ..
    }
}

Example 2: jquery check if all checkbox is not checked

$('#checkAll').click(function () {    
     $('input:checkbox').prop('checked', this.checked);    
 });