Hello Sebastian,

 

This is a browser side limitation.

You will have the same problem if you try to have multiple parallel ajax
call to a server.

 

Browsers, and I suppose flash is doing this too (but I’m no expert in what’s
going under the hood with flash), limit the number of requests to the same
domain at a value of 2. There is a regedit hack for having IE make it
bigger, but it’s not recommended.

 

This was introduced in pretty old versions of IE, Mozilla, etc. to both save
the bandwidth and the servers which had at that time some limitations
shorter than we have now, but the limitation still stands.

 

The best way for having many images loaded in parallel is to work on the
server side by having multiple DNS names pointing to the same server, like :

image1.mydomain.com/img1132.jpg

image2.mydomain.com/img2321.jpg

image….mydomain.com/img4785.jpg

imagen.mydomain.com/img1458.jpg

 

But once you get into this style of urls, you have to implement some sort of
hashing algorithm to make sure img1132.jpg will always come from domain
image1.mydomain.com or you’ll break both client caching (if you request the
same image from another server, the client is going to consider this is a
new image, so it won’t cache it), and any level of caching you may have
between your client and your image server (same thing, different domain =
different image).

 

 

You can make it happen in pure HTML by having a list of a few dozen images,
if you look in firebug, you’ll see it goes sequentially (by pair), and not
all in parallel.

 

Have a nice day,

Julien

 

  _____  

De : [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] De la part de Sebastian Wagner
Envoyé : mercredi 5 novembre 2008 16:02
À : Laszlo
Objet : [Laszlo-user] make Image calls parallel

 

I still am fighting with a way to get Image Loadings parallel / faster.
It seems to me that if you load Images, no matter if its DHTML or Flash the
sequence of loading is the sequence you init them... they just seem to go
out in sequence not parallel.

Is there a Browser Queue which forces the Image Loading in some sort of
sequence?
Are there Server-Side Limitations which force the Client to wait for
requests?
Is there a way to have some sort of Multi-Threaded Loading of Images in the
Client?

I've build some sample appz illustrating the problem / Issue:
Loading Images in a Loop:
http://openmeetings.googlecode.com/svn/trunk/openmeetings_lps411/test/images
/maindebug.lzx 
Loading in a Time-Driven Loop:
http://openmeetings.googlecode.com/svn/trunk/openmeetings_lps411/test/images
/maindebugTimer.lzx

the fun begins if you compare the loading Times of the requests in FireBug
in the Network Console. 
The Images at the end seem to be loaded later then the first image, or in
other words if you loop through 50 images and initialize them at the same
time it should be at *random* sequence loading. But the sequence is very
very close to the sequence you initialize the image-views. This looks like
sequence / queuing but it shouldn't ! Does not seem to matter if its DHTML
or SWF8.

thx,
sebastian

-- 
Sebastian Wagner
http://www.webbase-design.de
http://openmeetings.googlecode.com
http://www.laszlo-forum.de
[EMAIL PROTECTED]

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