gistfile1.js

$(document).ready(function() {
    var $book = $('#book')
    // wrapping the function in a closure
    ;(function display_icon() {
	$book.hide(1000, function() {
	    $book.show(1000, function() {
            	setTimeout(function() {
                    display_icon();
                }, 0);
            });
	});
    }()); // executing immediately
});