// $Id: popup_nav.js,v 1.1 2003/12/16 02:45:35 awilli07 Exp $
// routines for popup next, previous links
// requires utility.js
// popuplist is a list of popups (without .html extension)

// go to next page
function popup_next(popuplist) { return popup_loadpage(popuplist, 'next', 1) }
// go to previous page
function popup_prev(popuplist) { return popup_loadpage(popuplist, 'prev', -1) }

function popup_loadpage(popuplist, dir, mod) {
    var foo = "";
    var page = popup_page(popuplist);
    var a = utility_findanchor("popup_" + dir);
    //foo = "current page: " + page;
    page = (page + mod + popuplist.length) % popuplist.length;
    //foo += ", new page: " + page;
    //alert(foo);
    var url = popuplist[page] + ".html";
    //document.location = url
    //popup.location.replace(url);
    a.href = url;
    return true;
}

// work out what page we're on at the moment
// returns index in popuplist or 0 if not found
function popup_page(popuplist) {
    var file = document.location + "";  // cast to string
    file = basename(file);
    var j;
    if(j = file.indexOf('.')) file = file.substring(0, j);
    for(j = 0; j < popuplist.length; j++)
	if(popuplist[j] == file) return j;
    alert("page not found: " + file);
    return 0;  // page not found
}