Javascript replacement caused text replacment

It appears as if some javascript replacement inavetently cause text on the screen to be replaced. Here is the case in point: http://www.hallamshire.com/hsbim/1.1/programmersguide/overviewsamples.html

there was some text on that page that should have been displaed "open()" instead it was displayed somthing like "PrivoxyWindowOpen()" This was not a desirable effect.