I have a web application where there's a main page index.html that contains a button. The button loads a separate page.html file into an <object> element on the main page. The page.html file contains an <img> element that needs to load while offline. I'm able to load page.html into the <object> while offline, however for some reason the image is not loading.
Is this something that's possible. If so, what do I need to do?
Here's a simple example of what I have:
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Offline Web App</title>
<style>
body {
font-family: Arial, sans-serif;
text-align: center;
}
button {
padding: 10px 20px;
margin: 20px;
font-size: 16px;
}
</style>
</head>
<body>
<h1>Offline Web App</h1>
<button id="loadPage">Load Separate HTML Page</button>
<object id="contentFrame" width="100%" height="400px"></object>
<script>
document.getElementById('loadPage').addEventListener('click', () => {
document.getElementById('contentFrame').data = 'page.html';
});
</script>
<script>
if ('serviceWorker' in navigator) {
window.addEventListener('load', () => {
navigator.serviceWorker.register('service-worker.js')
.then(registration => {
console.log('Service Worker registered:', registration);
})
.catch(error => {
console.error('Service Worker registration failed:', error);
});
});
}
</script>
</body>
</html>
service-worker.js:
const CACHE_NAME = 'offline-cache-v6';
const ASSETS_TO_CACHE = [
'/app/index.html', // Main app page
'/app/page.html', // Page loaded in <object>
'/app/service-worker.js', // This file itself
'/app/img.png' // Image on page.html
];
self.addEventListener('install', event => {
event.waitUntil(
caches.open(CACHE_NAME)
.then(cache => cache.addAll(ASSETS_TO_CACHE))
);
});
self.addEventListener('fetch', event => {
event.respondWith(
caches.match(event.request)
.then(response => {
if (response) {
return response; // Return cached asset
}
return fetch(event.request)
.then(response => {
// Check if we received a valid response
if(!response || response.status !== 200 || response.type !== 'basic') {
return response;
}
// Clone the response. A response is a Stream and already read.
// We want to use it in the browser and in the cache.
const responseToCache = response.clone();
caches.open(CACHE_NAME)
.then(cache => {
return cache.put(event.request, responseToCache);
});
return response;
});
})
);
});
self.addEventListener('activate', (event) => {
const cacheWhitelist = [CACHE_NAME];
event.waitUntil(
caches.keys().then((cacheNames) => {
return Promise.all(
cacheNames.map((cacheName) => {
if (cacheWhitelist.indexOf(cacheName) === -1) {
return caches.delete(cacheName);
}
})
);
})
);
});
page.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Page</title>
</head>
<body>
<h2>This is a Separate HTML Page</h2>
<img src="/app/img.png" alt="Cached Image" width="300">
</body>
</html>