Most modern web sites, when asking for a browser, specify modern versions so
their content can load and work within their parameters. This likely means new
enough to have more secure online presence, flash player update, and so on.
There is no modern Safari for older PowerPC Mac, Tiger 10.4.11, Leo 10.5.8.
No Explorer, no FireFox, etc.
Have you tried TenFourFox? http://www.floodgap.com/software/tenfourfox/
How about iCab? http://www.icab.de/dl.php
(SeaMonkey for PPC requires a mac running OS X 10.5.8 to use it)
Adobe Flash for PowerPC Mac, Tiger 10.4.11, and Leopard 10.5.8 is not
updated; there is an older version for use in these systems, only. Latest
versions of these do not work. Finding the older ones is a tedious effort.
•Flash Player Help - Adobe Flash Player:
http://helpx.adobe.com/flash-player.html
•Adobe Flash Player - Other Versions (old Mac)
http://get.adobe.com/flashplayer/otherversions/
•Flash Player Problems with Mac OS:
http://helpx.adobe.com/flash-player/kb/installation-problems-flash-player-mac.ht ml
What version Mac OS X is the iBook G4 running?
How much RAM is installed?
With a processor faster than 867MHz the PPC Macs can run Leopard 10.5.8;
however it may be hard to get a retail install DVD, not grey system disc from
other computer, those won't work.
I'd suspect no financial or bank web sites with secure certificates would
allow some older obsolete browser versions, since they may be trouble.
Good luck! 😐