var Unselectable = {

    enable : function(e) {
        var e = e ? e : window.event;

        if (e.button != 1) {
            if (e.target) {
                var targer = e.target;
            } else if (e.srcElement) {
                var targer = e.srcElement;
            }

            var targetTag = targer.tagName.toLowerCase();
            if ((targetTag != "input") && (targetTag != "textarea")) {
                return false;
            }
        }
    },

    disable : function () {
        return true;
    }

}

if (typeof(document.onselectstart) != "undefined") {
    document.onselectstart = Unselectable.enable;
} else {
    document.onmousedown = Unselectable.enable;
    document.onmouseup = Unselectable.disable;
}