appstore.redirect.js

var COOKIE_NAME = 'iphone_redirect';

$go = $.cookie(COOKIE_NAME);

function appstore() {
    var answer = confirm("Download the FREE \nTorbay Hotels App today")
    if (answer) window.location = "http://itunes.apple.com/app/id532107287?mt=8";
    $.cookie(COOKIE_NAME, 'notice', { path: '/', expires: 10})
}

function isiPhone(){
    return (
        (navigator.platform.indexOf("iPhone") != -1) ||
        (navigator.platform.indexOf("iPod") != -1) ||
                (navigator.platform.indexOf("iPad") != -1)
    );
}

if(isiPhone() && $go == null) appstore();

jquery.cookie.js

/**
 * jQuery Cookie plugin
 *
 * Copyright (c) 2010 Klaus Hartl (stilbuero.de)
 * Dual licensed under the MIT and GPL licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 *
 */
jQuery.cookie = function (key, value, options) {

    // key and at least value given, set cookie...
    if (arguments.length > 1 && String(value) !== "[object Object]") {
        options = jQuery.extend({}, options);

        if (value === null || value === undefined) {
            options.expires = -1;
        }

        if (typeof options.expires === 'number') {
            var days = options.expires, t = options.expires = new Date();
            t.setDate(t.getDate() + days);
        }

        value = String(value);

        return (document.cookie = [
            encodeURIComponent(key), '=',
            options.raw ? value : encodeURIComponent(value),
            options.expires ? '; expires=' + options.expires.toUTCString() : '', // use expires attribute, max-age is not supported by IE
            options.path ? '; path=' + options.path : '',
            options.domain ? '; domain=' + options.domain : '',
            options.secure ? '; secure' : ''
        ].join(''));
    }

    // key and possibly options given, get cookie...
    options = value || {};
    var result, decode = options.raw ? function (s) { return s; } : decodeURIComponent;
    return (result = new RegExp('(?:^|; )' + encodeURIComponent(key) + '=([^;]*)').exec(document.cookie)) ? decode(result[1]) : null;
};