Browser differences in mouse events in the body of a web page

Using <body onclick="userfunction( )"> does not typically work in Netscape or Mozilla. 

Though it seems like, on occasion, I have gotten that most simple thing to work, I cannot generally remember what quirky things I may have done differently from one time to the next. What seems to be the difference is illustrated in the script associated with the current page:

 This causes the current page to fire one event when the document is clicked on in Internet Explorer and two events from Mozilla (Firefox 1.0) or Netscape (7.1).