//get correct value

function navSel(selNum){

  if(String(selNum).length == 1) {
  selNum = "0"+String(selNum);
}

//assemble URL and create link for selections

var chapterURL = "section"+selNum+".html";
chapterChosen = selNum
location.replace(chapterURL);
}

function netSource(){
var chapterURLNet = "http://vig.prenhall.com/catalog/academic/discipline/1,4094,3830,00.html";
location.replace(chapterURLNet);
}

function messageBoard(){
var boardURL = "section04.html";
location.replace(boardURL);
}