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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Hello Sebastian,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>This is a browser side limitation.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>You will have the same problem if you try
to have multiple parallel ajax call to a server.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>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.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>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.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>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 :<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>image1.mydomain.com/img1132.jpg<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>image2.mydomain.com/img2321.jpg<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>image….mydomain.com/img4785.jpg<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>imagen.mydomain.com/img1458.jpg<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>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).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>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.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Have a nice day,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Julien<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>De :</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
laszlo-user-bounces@openlaszlo.org [mailto:laszlo-user-bounces@openlaszlo.org] <b><span
style='font-weight:bold'>De la part de</span></b> Sebastian Wagner<br>
<b><span style='font-weight:bold'>Envoyé :</span></b> mercredi 5 novembre
2008 16:02<br>
<b><span style='font-weight:bold'>À :</span></b> Laszlo<br>
<b><span style='font-weight:bold'>Objet :</span></b> [Laszlo-user] make
Image calls parallel</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I still am fighting with a way to get Image Loadings parallel / faster.<br>
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.<br>
<br>
Is there a Browser Queue which forces the Image Loading in some sort of
sequence?<br>
Are there Server-Side Limitations which force the Client to wait for requests?<br>
Is there a way to have some sort of Multi-Threaded Loading of Images in the
Client?<br>
<br>
I've build some sample appz illustrating the problem / Issue:<br>
Loading Images in a Loop:<br>
<a
href="http://openmeetings.googlecode.com/svn/trunk/openmeetings_lps411/test/images/maindebug.lzx">http://openmeetings.googlecode.com/svn/trunk/openmeetings_lps411/test/images/maindebug.lzx</a>
<br>
Loading in a Time-Driven Loop:<br>
<a
href="http://openmeetings.googlecode.com/svn/trunk/openmeetings_lps411/test/images/maindebugTimer.lzx">http://openmeetings.googlecode.com/svn/trunk/openmeetings_lps411/test/images/maindebugTimer.lzx</a><br>
<br>
the fun begins if you compare the loading Times of the requests in FireBug in
the Network Console. <br>
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.<br>
<br>
thx,<br>
sebastian<br clear=all>
<br>
-- <br>
Sebastian Wagner<br>
<a href="http://www.webbase-design.de">http://www.webbase-design.de</a><br>
<a href="http://openmeetings.googlecode.com">http://openmeetings.googlecode.com</a><br>
<a href="http://www.laszlo-forum.de">http://www.laszlo-forum.de</a><br>
<a href="mailto:seba.wagner@gmail.com">seba.wagner@gmail.com</a><o:p></o:p></span></font></p>
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