savegame data is gone after clearing iPad history

Game data that has been saved using the savegame system object is deleted when clearing the browser history. I have tested the attached project on a windows PC, an iMac and an iPad.

On the desktop machines it works fine. You can empty all the browser histories and caches and then reload your saved game data.

If you play this on an iPad, save the game state, clear all browser history and caches, refresh the game and try loading, all data is gone.

A live version of the game is here: http://fungooms.com/Test/

This might not be a bug - it may just be an anomaly of the iPad, but it does say on Scirra's site "Savegames are not saved in the cache. The browser cache is a very much temporary storage......."

https://dl.dropboxusercontent.com/u/15741639/iPad%20Bug/iPadbug.capx

Description

A simple game that lets you paint circles on the screen and either save or load the pattern

Steps To Replicate

• Run the game on an iPad
• Draw circles anywhere by clicking and moving the mouse or touching the screen
• Click or Touch SAVE to save your progress
• To test that your progress is saved, refresh the page and load your last pattern.
• Clear all browser history and empty browser caches][Run the game and click LOAD

Observed Results

The work that you did is not loaded. It appears that clearing the history has deleted your data.

Expected Results

As what happens on desktop, your data should be loaded back even after clearing history.

Affected Browsers

• Chrome: (YES)
• Safari: (YES)
• Firefox: (YES)
• Internet Explorer: (NO)

Operating System and Service Pack

iOS 9.2.1

Release 221, 64-Bit, Personal License

This is not a bug. Browsers are designed to leave the user in control. If some game was storing 500mb+ of savegame data, then browsers provide these features to allow the user to easily get their space back. All storage by any web page is subject to this, and by design there's no way for websites to override this (or they could clog up people's systems with tons of data that is unremovable).

The cache is temporary storage which can be evicted at any time for more or less any reason, and savegame data does go in to more persistent storage which basically remains there indefinitely until the user clicks a button saying "I want to delete that data", and consequently, it's deleted! Other platforms like NW.js, Cordova and others are not affected, because they don't use the browser storage at all.

I think you've identified Safari as different mainly because it doesn't provide any granularity - all you can do is press a button that clears *everything*. In most other browsers such as Chrome you get a list of checkboxes to decide what to clear. Each browser defines this differently, but usually the checkbox which mentions "cookies", "website data", "offline data" or "app data" covers this kind of storage. If you don't tick that, it's preserved; in Safari it just wipes everything.