HTML5 on iPhone Safari - data stored by localStorage does not always persist. Why?_问答_开发者

HTML5 on iPhone Safari - data stored by localStorage does not always persist. Why?

开发者 https://www.devze.com 2022-12-27 02:45 出处：网络

I write a simple iPhone web app using HTML5\'s localStorage. Tests on a 2G device show that data stored using localStorage does not persist after the Safari process is killed although the opened Safar

I write a simple iPhone web app using HTML5's localStorage.

Tests on a 2G device show that data stored using localStorage does not persist after the Safari process is killed although the opened Safari windows are remembered.

The data is also lost in a case where I am on a different site on a different Safari window, then I change the window to where the web app in subject is shown. Whe开发者_Python百科n Safari loads the page it automatically refreshes the page. Then the data is lost. This is a simple test code:

<html>
<head>
    <meta name="viewport" content="height=device-height, width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
</head>
<body>
<script>
    alert("1:" + localStorage.getItem("test"));
    localStorage.setItem("test", "123");
    alert("2:" + localStorage.getItem("test"));
</script>
</body>

As far as I understand the data should persist!

Can anyone shed some light on this behavior? What should I do to get the persistence to work?

Thanks!

Tom.

According to Apple (https://developer.apple.com/library/archive/documentation/iPhone/Conceptual/SafariJSDatabaseGuide/Name-ValueStorage/Name-ValueStorage.html#//apple_ref/doc/uid/TP40007256-CH6-SW3), localStorage support was added in Safari 4.0.

According to Wikipedia (https://en.wikipedia.org/wiki/Safari_version_history), Safari 4.0 was added in iPhone OS 3.0.

2G iPhones did not come with OS 3.0 or later pre-installed. Your iPhone OS version is most likely too old.

I think there is a bug with local storage in iPhone Safari. I have a similar problem as you: http://groups.google.com/group/phonegap/browse_thread/thread/746868e928aaba5c

I tried your code on my iPhone 3G and Safari on Windows and it works. Maybe you are running an older version of Safari on your iPhone?