a web interface to identify()

i have a function like this:
  # show a plot and run a script when the user clicks on a plot,
  # where the script arguments correspond to the user-selected point.
  blah <- function(x, y) {
    plot(y~x)
    n <- identify(x=x, y=y)
    com <- system(command=paste("bleh", names(y)[n]))
  }

i would like to do this via a web page instead of x11() etc.  eg:
  1) a user clicks on an image in their web browser
  2) the i,j coordinate is sent to the server
  3) a single R process determines the nearest data point
  4) the server sends a new page to the client, based on attributes  
of the selected data point

i've browsed the R web interface options and frankly don't know which  
to pick, or maybe they are all overkill for what i am trying to  
accomplish?  perhaps the easiest thing to do is use ismap to capture  
the i,j coords, the receiving cgi script connects to an R process for  
the data lookup, and then responds to the browsing client  
appropriately.  the data set involved is very large, so i'd need a  
single R process sitting there waiting for such queries in order to  
avoid initialize&load time - this is the part i am particularly  
unclear how to do.

any ideas/suggestions/guidance on the best approach would be much  
appreciated.  thank you.