// JS Utilities by Robert P. Levy, Copyright 2008 Robert P. Levy, see GNU Public License

var browserType;

if (document.layers) {browserType = "nn4"}
if (document.all) {browserType = "ie"}
if (window.navigator.userAgent.toLowerCase().match("gecko")) {
    browserType= "gecko"
}

function getById(id,doc) {
    if (!doc) doc = document;
    if (browserType == "gecko" ) el = doc.getElementById(id);
    else if (browserType == "ie") el = doc.getElementById(id);
    else el = doc.all[id];
    return el;
}

function modById(id,fn,change) {
    el = getById(id);
    if (change) el=fn(el);    
    else return fn(el);
}

// show and hide 

function hideVis(id) { modById(id, function (e) { e.style.visibility = "hidden"; }, true ) }
function showVis(id) { modById(id, function (e) { e.style.visibility = "visible"; }, true ) }
function hideDis(id) { modById(id, function (e) { e.style.display = "none"; }, true ) }
function showDis(id) { modById(id, function (e) { e.style.display = "inline"; }, true ) }

// assumes two two divs with a shared base name and the following suffixes
var textDivSuf = "TextDiv";  
var edDivSuf = "EdDiv";
function switchTextToEdit(id) { hideDis( id + textDivSuf ); showDis( id + edDivSuf ) }
function switchEditToText(id) { hideDis( id + edDivSuf ); showDis( id + textDivSuf ) }

// list processing

function cdr(l) {return l.slice(1);}

// String formatting

function removeExtraSpaces(s) {
    s = s.replace(/\s+/,' ');
    return s;}

function titleCase(s) {
    s = removeExtraSpaces(s.toLowerCase());
    s = s.substr(0,1).toUpperCase()+s.substr(1);
    pos = s.indexOf(' ',1);
    while ( pos > 0 ) {
	s = s.substr(0,pos)+' '+s.substr(pos+1,1).toUpperCase()+s.substr(pos+2);
	pos = s.indexOf(' ',pos+1);}
    return s;}

// form and DOM processing functions

function checkBoxData(chkbx) {
    chkbxary=Array();
    for (var i=0; i < chkbx.length; i++) if ( chkbx[i].checked ) chkbxary.push(chkbx[i].value); 
    return chkbxary }

function optionBoxData(opbx) {
    opbxary=Array();
    for (var i=0; i < opbx.length; i++) if ( opbx[i].selected ) opbxary.push(opbx[i].value); 
    return opbxary }

function getSelected(opbx) {
    return opbx[opbx.selectedIndex].value }

// inner html functions

// note: refactor these 3 functions to share some of the same code
// also apply this idea from http://domscripting.com/blog/display/99:
//First of all, use the DOM to create a block level element—such as a div—using createElement. Then update the innerHTML property of this newly-created element. Finally, insert the updated element into the document using a DOM method like appendChild or insertBefore:
//var newdiv = document.createElement("div");
//newdiv.innerHTML = xhr.responseText;
//var container = document.getElementById("container");
//container.appendChild(newdiv);

function getContent(id) {
    if (document.getElementById || document.all) {
	var el = document.getElementById? document.getElementById(id): document.all[id];
	if (el && typeof el.innerHTML != "undefined") return el.innerHTML}}

// change inner html 

function changeContent(id,shtml) {
    if (document.getElementById || document.all) {
	var el = document.getElementById? document.getElementById(id): document.all[id];
	if (el && typeof el.innerHTML != "undefined") el.innerHTML = shtml;}}

// change inner html 

function appendContent(id,shtml) {
    if (document.getElementById || document.all) {
	var el = document.getElementById? document.getElementById(id): document.all[id];
	if (el && typeof el.innerHTML != "undefined") el.innerHTML = el.innerHTML + shtml;}}


// AJAX tools

// generate a request object

function genRequest() {
    if (window.XMLHttpRequest) {
	req = new XMLHttpRequest();  }
    else if (window.ActiveXObject) {
	req = new ActiveXObject("Microsoft.XMLHTTP");}
    return req;}

// AJAX request (HOF): make a request and then apply a function on the result

function makeRequest(url,fun) { 
    req=genRequest(); 
    req.onreadystatechange=function() {
	if (req.readyState==4) {
	    fun(req);}}
    req.open('get', url, true);
    req.send(null);}

// pluralizer of the above -- make one cascading sequence of requests
/*
function makeRequests(urlList,funList) { 
    makeRequest(urlList[0],
		function (req) { 
		    funList[0](req); // funList[0] is a closure
		    if (urlList.length > 2) { // urlList is a closure too
			makeRequests(cdr(urlList),cdr(funList));}
		    else {
			makeRequest(urlList[1],funList[1]);}});}
*/

/* alternate approach
function makeRequests(urlList,funList) { 
    req=genRequest(); 
    req.onreadystatechange=function() {
	if (req.readyState==4) {
	    funList[0](req);
	    if (urlList.length > 2) {
		makeRequests(cdr(urlList),cdr(funList));}
	    else {
		makeRequest(urlList[1],funList[1]);}}}
    req.open('get', urlList[0], true);
    req.send(null);}
*/

// simplified request function that applies the text directly
// add later: report error as an alert, with optional div id for error report

function requestChange(url,id) {
    makeRequest(url,function (r) {
	    changeContent(id,r.responseText);});}

// url loader using cookie instead of query string so as to maintain state consistently

function loadUrl(url,variable,value,cookiepath) {
    createCookie(variable,value,30,cookiepath);
    window.location.href=url;}

// various

function nothing() {}

// cookies
// copied from some website, slightly modified

function createCookie(name,value,days,path) {
    if (days) {
	var date = new Date();
	date.setTime(date.getTime()+(days*24*60*60*1000));
	var expires = "; expires="+date.toGMTString();
    }
    else var expires = "";
    document.cookie = name+"="+value+expires+"; path="+path;
}
function readCookie(name) {
    var nameEQ = name + "=";
    var ca = document.cookie.split(';');
    for(var i=0;i < ca.length;i++) {
	var c = ca[i];
	while (c.charAt(0)==' ') c = c.substring(1,c.length);
	if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
    }
    return null;
}
function eraseCookie(name) {
    createCookie(name,"",-1);
}