$(document).ready(function () {

    var screenWidth = screen.width;
    var screenHeight = screen.height;

    var mainColumnWidth = $('#col_center').width();

    var sideWidth = ((screenWidth - mainColumnWidth) / 2) - 10;

    $('#col_left, #col_right').css({ width: sideWidth });
    $('#col_left, #col_right, #col_center').css({ minHeight: screenHeight });

    $('#main_menu ul li:last').addClass("last");
});