/* ************** Javascript file used to switch stylesheets ************ */

/* sets the active stylesheet to the specified one */
function setActiveStyleSheet(title) 
{
    var i, a, main;
    for (i=0; (a= document.getElementsByTagName("link")[i]); i++) 
	{
	    if (a.getAttribute("rel").indexOf("style") != -1 && a.getAttribute("title")) 
		{
		    a.disabled= true;
		    if (a.getAttribute("title") == title) a.disabled= false;
		} // end if
	} // end loop
} // end function setActiveStyleSheet()

// --------------------------------

/* returns the title of the active stylesheet */
function getActiveStyleSheet() 
{
    var i, a;
    for (i=0; (a= document.getElementsByTagName("link")[i]); i++) 
	{
	    if (a.getAttribute("rel").indexOf("style") != -1 && 
		a.getAttribute("title") && !a.disabled)
		return a.getAttribute("title");
	} // end loop
    return null;
} // end function getActiveStyleSheet()

// -------------------------------

/* returns the title of the preferred stylesheet */
function getPreferredStyleSheet() 
{
    var i, a;
    for (i=0; (a= document.getElementsByTagName("link")[i]); i++)
	{
	    if (a.getAttribute("rel").indexOf("style") != -1
		&& a.getAttribute("rel").indexOf("alt") == -1
		&& a.getAttribute("title"))
	        return a.getAttribute("title");
	} // end loop
    return null;
} // end function getPreferredStyleSheet()

// --------------------------------

/* creates a cookie with a name, value, and expiration time in days */
function createCookie(name,value,days) 
{
    if (days) 
	{
	    var date = new Date();
	    date.setTime(date.getTime() + (days*24*60*60*1000));
	    var expires= "; expires=" + date.toGMTString();
	} // end if
    else expires= "";
    document.cookie= name + "=" +value + expires + "; path=/";
} // end function createCookie()

// ----------------------------

/* returns the specified cookie */
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);
	} // end loop
    return null;
} // end method readCookie()

// -----------------------------

/* change the active (preferred) stylesheet to the selected one and save it */
function doChangeAndSave(selBox)
{
    var selIndex= selBox.selectedIndex; // get the selected index
    var title= selBox.options[selIndex].value; // get the value of this index
    if (title == "-1") return false;
    setActiveStyleSheet(title); // do the actual switch
} // end method doChangeAndSave()

// -----------------------------

window.onload = function(e) {
  var cookie= readCookie("style");
  var title= cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);
}

window.onunload = function(e) {
  var title= getActiveStyleSheet();
  createCookie("style", title, 365);
}

var cookie= readCookie("style");
var title= cookie ? cookie : getPreferredStyleSheet();
setActiveStyleSheet(title);