function preloadimages() {
	for (i=0;i<bilder_new.length;i++){
		n_images[i]=new Image();
		n_images[i].src=bilder_new[i];
		o_images[i]=new Image();
		o_images[i].src=bilder_old[i];
	}
}

function new_img(id,inte) {document.getElementById(id).src = n_images[inte].src;}

function old_img(id, inte) {document.getElementById(id).src = o_images[inte].src;}

function showLogin() {
    var login_bg = $("#login_background");
    var login_form = $("#login_field");
    
    //login_bg.show();
    login_bg.fadeIn();
    login_form.fadeIn();
}

function hideLogin(){
    var login_bg = $("#login_background");
    var login_form = $("#login_field");
   
    login_bg.fadeOut();
    login_form.fadeOut();
}
function displayError(error){
    $('#messages').html(error);
}