var app = {
    isIE:       (navigator.userAgent.indexOf('MSIE')  > 0),
    isGecko:    (navigator.userAgent.indexOf('Gecko') > 0),
    isOpera:    (navigator.userAgent.indexOf('Opera') > 0),

    get: function(id) {
        return document.getElementById(id);
    },

    onload: function(func) {
        var oldonload = window.onload;
        if (typeof window.onload != 'function') {
            window.onload = func;
        } else {
            window.onload = function() {
                if (oldonload) {
                    oldonload();
                }
                func();
            }
        }
    }

}