[whatwg] should async scripts block the document's load event?

[Steve Souders]

ASYNC should not block the onload event. Thinking of the places where 
ASYNC will be used, they would not want onload to be blocked.

-Steve

On 2/12/2010 11:50 AM, Jonas Sicking wrote:
> It's a good point. Curious to hear what other people are thinking.
>
> / Jonas
>
> On Fri, Feb 12, 2010 at 10:10 AM, Nicholas Zakas<nzakas at yahoo-inc.com>  wrote:
>    
>> To me “asynchronous” fundamentally means “doesn’t block other things from
>> happening,” so if async currently does block the load event from firing then
>> that seems very wrong to me.
>>
>>
>>
>> -Nicholas
>>
>>
>>
>> ______________________________________________
>>
>> Commander Lock: "Damnit Morpheus, not everyone believes what you believe!"
>>
>> Morpheus: "My beliefs do not require them to."
>>
>> ________________________________
>>
>> From: whatwg-bounces at lists.whatwg.org
>> [mailto:whatwg-bounces at lists.whatwg.org] On Behalf Of Brian Kuhn
>> Sent: Friday, February 12, 2010 8:03 AM
>> To: Jonas Sicking
>> Cc: Steve Souders; WHAT Working Group
>> Subject: Re: [whatwg] should async scripts block the document's load event?
>>
>>
>>
>> Right.  Async scripts aren't really asynchronous if they block all the
>> user-visible functionality that sites currently tie to window.onload.
>>
>>
>>
>> I don't know if we need another attribute, or if we just need to change the
>> behavior for all async scripts.  But I think the best time to fix this is
>> now; before too many UAs implement async.
>>
>>
>>
>> -Brian
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Thu, Feb 11, 2010 at 10:41 PM, Jonas Sicking<jonas at sicking.cc>  wrote:
>>
>> Though what we want here is a DONTDELAYLOAD attribute. I.e. we want
>> load to start asap, but we don't want the load to hold up the load
>> event if all other resources finish loading before this one.
>>
>> / Jonas
>>
>> On Thu, Feb 11, 2010 at 10:23 PM, Steve Souders<whatwg at souders.org>  wrote:
>>      
>>> I just sent email last week proposing a POSTONLOAD attribute for scripts.
>>>
>>> -Steve
>>>
>>> On 2/10/2010 5:18 PM, Jonas Sicking wrote:
>>>        
>>>> On Fri, Nov 6, 2009 at 4:22 PM, Brian Kuhn<bnkuhn at gmail.com>    wrote:
>>>>
>>>>          
>>>>> No one has any thoughts on this?
>>>>> It seems to me that the purpose of async scripts is to get out of the
>>>>> way
>>>>> of
>>>>> user-visible functionality.  Many sites currently attach user-visible
>>>>> functionality to window.onload, so it would be great if async scripts at
>>>>> least had a way to not block that event.  It would help minimize the
>>>>> affect
>>>>> that secondary-functionality like ads and web analytics have on the user
>>>>> experience.
>>>>> -Brian
>>>>>
>>>>>            
>>>> I'm concerned that this is too big of a departure from how people are
>>>> used to<script>s behaving.
>>>>
>>>> If we do want to do something like this, one possibility would be to
>>>> create a generic attribute that can go on things like<img>,<link
>>>> rel=stylesheet>,<script>    etc that make the resource not block the
>>>> 'load' event.
>>>>
>>>> / Jonas
>>>>
>>>>          
>>>        
>>
>>