Why was HTML5 Web Workers support removed from the Android browser in versions 2.2 and up?

I'm trying to learn something about JavaScript threading. And from a tutorial I learned about HTML5 API web worke开发者_如何学Cr. This API enables JavaScript multi-threading. So I start to figure out how and where can I use this feature.

Form http://caniuse.com/#search=worker

I find this API is only supported in lower version of Android browser. It is unavailable in Android 2.2 and later.

Is this result correct? If it is, is it because of the performance consideration?

On which version will this API be available?

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from config.h of Android 2.2.

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commit 68698168e7547cc10660828f1fb82be7a8efa845

Author: Steve Block

Date: Wed Mar 17 14:37:19 2010 +0000

Disable workers

This is because V8 on Android does not have the required locking. Also disables channel messaging, which is used only with workers.

Bug: 2522239

Change-Id: I6cb91b4048c7e1a0351e422561625397a2e98986

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via http://code.google.com/p/android/issues/detail?id=10004#c7

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Regarding when the API will be available, Web Workers (but not shared workers) are now available in Chrome Mobile, available only for ICS (Android 4.0) and higher devices.

Note that the built-in browser on Android 4 does not support workers; you must install Chrome.

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• Web Workers are available again on the built-in Android Browser since 4.4
• Shared Workers are still unsupported on both Android Browser and Chrome for Android.