var menu = {
    selection: null,
    id_locked: null,
    lock: function(selector) {
        this.id_locked = selector;
    },
    init: function() {
        if (this.id_locked != null) {
            document.getElementById('menu-selector'+this.id_locked).className = 'menu-selectors menu-selected';
        }
    },
    select: function(selector){
        if (this.selection != null) this.selection.className = 'menu-selectors menu-unselected';
        if (selector != this.id_locked){
            this.selection = document.getElementById('menu-selector'+selector);
            this.selection.className = 'menu-selectors menu-selected';
        }
    },
    unselect: function(selector){
        if (this.selection != null) this.selection.className = 'menu-selectors menu-unselected';
        if (selector != this.id_locked){
            this.selection = document.getElementById('menu-selector'+selector);
            this.selection.className = 'menu-selectors menu-unselected';
        }
        this.selection = null;
    }
}