if (window.screen.width > 800) {
    document.getElementById('MasterColumn02').style.display = "";
    document.getElementById('MasterColumn04').style.display = "";
    document.getElementById('MasterColumn03').style.width = (document.body.clientWidth - (document.body.clientWidth * (20 / 100))); 
     
}
else {
    document.getElementById('MasterColumn02').style.display = "none";
    document.getElementById('MasterColumn04').style.display = "none";
    document.getElementById('MasterColumn03').style.width ="800px"; 
}