function leave_site (next_site) {
   var msg= "You are now leaving 'www.cda.ca'.\n" ;
   msg += "The site '" ;
   msg += next_site ;
   msg += "' is not under the direction of the Canadian Dam Association.\n" ;
   msg += "Click 'OK' to open a new window and proceed." ;
   alert(msg) ;
   return true ;
}