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Dynamically loaded scripts with 304s responses interrupt the currently executing JS thread onload. by Satyen Desai


 as Won't Fix Help for as Won't Fix

Type: Bug
ID: 763871
Opened: 9/20/2012 2:47:02 PM
Access Restriction: Public
User(s) can reproduce this bug


If you load scripts dynamically, with the async property set to true (or default async operation), under certain circumstances (in this case, when you load scripts from the onload callback of a link element - but there may be others), and the scripts result in 304s, the onload handler for the dynamically loaded script interrupts the currently executing JS thread to execute the onload handler (that is, the onload handler is invoked synchronously in this case), and then returns to the previously executing script.

This fundamentally changes the JS order-of-execution, and also differs from the behavior when the scripts result in 200 responses (where onload is invoked asynchronously) - making it impossible to figure out which flow will be encountered.

The test case has complete details.
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Posted by Microsoft on 11/29/2012 at 1:51 PM
Thank you for your feedback.

At this time we do not plan to fix this issue. Every piece of feedback we receive is important to us and helps us improve the quality of Internet Explorer. Unfortunately, we are currently unable to address your feedback. We will consider fixing this issue in the future.

We continue to welcome more feedback, so please don't hesitate to report other ways that we can improve Internet Explorer.

Best regards,

The Internet Explorer Team
Posted by Microsoft on 9/20/2012 at 5:18 PM
Thank you for your feedback. We will be investigating this issue further.

Best regards,

The Internet Explorer Team
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