as Marc pointed out, there was a problem with my javascript use that showed up as an event error in firefox. Miguel has suggested how to remove that issue. i've also added commands to set the colour explicitly, and to move to the origin after translation, so that firefox now draws whole squares, rather than leaving out the first line. having just upgraded my opera (so much smaller and easier than full gui libs;-), the modified code appears to work with opera (9.22) and firefox (1.5.0.6), on windows, using ghc 6.6.1. to avoid spamming this list, i've put the updated code and a couple of screenshots online at: http://www.cs.kent.ac.uk/~cr3/toolbox/haskell/browsing/ please note that this code is not at all pretty, but is meant to show most of the necessary pieces. if you want to use the idea seriously, the haskell code would need cleaning up, the html/javascript would need checking for standard compliance (there are several standards involved, so it is tempting to code by modifying examples, which are not always correct, even if they work on some browser). you might also want to consider using one of the many javascript/ ajax browser gui frameworks, if only to isolate you from browser incompatibilities. but even if you code to a single standard-compliant browser, your clients might find it easier to download and install that than a full gui-lib binding. hth, claus