Answers for "how to set checked checkbox value in javascript"

javascript check uncheck checkbox

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

get the state of a checkbox

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