On 4 Jan 2008 at 12:25, Wolfgang Büscher wrote:

> If we have a Javascript expert here: Any idea how a Javascript
> (embedded in an HTML document) can detect if all embedded graphics
> have been updated ? In that case, the "refresh" interval could be
> restarted after the previous refresh is finished.
> 

Well just got round to looking at this grabber after reading all the 
mails. Exactly the same here....

Firstly, note we are indeed talking about Javascript here, earlier 
emails talked about Java. How many times do we have to tell people 
that Javascript (common browser scripting language, sometimes called 
EcmaScript) and Java (compiled programming language from Sun) are 
completely different things and must never be confused. Mark's site 
certainly contains no Java applets.....

The basic problem is that each grabber image is 1.2Mb in size (not 
sure if that is typical of grabbers?). If Mark is using a normal ADSL 
connection the upload speed of that seriously affects the issue. 
Plain ADSL upload will be around 20kbytes/sec, ADSLMax around 
40kbytes/second. For that reason it takes ages to upload a single 
image - it takes around 30 seconds here on my 2Mb ADSL which is 
correct for a 40kbyte/sec upload - or much longer if there are 
several people connected. Bear in mind if you are on a monthly 
restricted usage limit all of us trying your grabber will soon use up 
your allowance, especially if people leave it on all the time!!

So I am not sure if changing the javascript refresh will help, you 
really need to either reduce the size of the images by a big margin 
or similarly increase the refresh time. Or maybe do not set a refresh 
time but get users to do a refresh. Not sure how John GM4SLV does it, 
maybe you should find out.

73 Dave G3YMC (still off the air on 500k)

http://www.davesergeant.com