var sections = new Array('side-1', 'side-2');
function init() {
    show('side-1');
 }
function show(section) {
    for (var i = 0; i < sections.length; i++) {
        if (sections[i] == section) {
            document.getElementById(sections[i]).style.display = 'block';
        } else {
            document.getElementById(sections[i]).style.display = 'none';
        }
    }
};