Peter Lubbers - Pro HTML 5 Programming

}
if (!window.localStorage) {
log("HTML5 Local Storage not supported in your browser.");
return;
}
if (!window.WebSocket) {
log("HTML5 WebSocket is not supported in your browser.");
return;
}
CHAPTER 10 ■ CREATING HTML5 OFFLINE WEB APPLICATIONS
log("Initial cache status: " + showCacheStatus(window.applicationCache.status));
document.getElementById("installButton").onclick = install;
Adding the Update Button Handler
Next, add an update handler that updates the application cache as follows:
install = function() {
log("Checking for updates");
try {
window.applicationCache.update();
} catch (e) {
applicationCache.onerror();
}
}
Clicking this button will explicitly start the cache check that will cause all cache resources to be
downloaded if necessary. When available updates have completely downloaded, a message is logged in
the UI. At this point, the user knows that the application has successfully installed and can be run in
offline mode.
Add Geolocation Tracking Code
This code is based on the geolocation code from Chapter 4. It is contained in the tracker.js JavaScript
file.
/*
* Track and report the current location
*/
var handlePositionUpdate = function(e) {
var latitude = e.coords.latitude;
var longitude = e.coords.longitude;
log("Position update:", latitude, longitude);
if(navigator.onLine) {
uploadLocations(latitude, longitude);
}
storeLocation(latitude, longitude);
}
255