// JavaScript Document

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;
    	}
  	}
}
 
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");
  	}
  	return null;
}
 
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");
  	}
  	return null;
}
 
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();
  	}
  	else
		expires = "";
  	document.cookie = name+"="+value+expires+"; 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 leerEstilo()
{
	var cookie = readCookie("style");
  	var title;
  	if(cookie == null)
	{
  		title = "verde";	
	}
	else
	{
  		title = cookie ? cookie : getPreferredStyleSheet();
  	}
  	setActiveStyleSheet(title);
}
 
function guardarEstilo()
{
	var title = getActiveStyleSheet();
	createCookie("style", title, 365);
}