function setActiveStyleSheet(title) {
    var i, a, main;
    var listo = 0;
    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){
                listo = 1;
                a.disabled = false;
            }
        }
    }
    if(listo == 0) {
    	document.getElementsByTagName("link")[0].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;
}

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);


function estiloMenos() {
    estiloActual = getActiveStyleSheet();
    numEstiloActual = (estiloActual.substring(6,7)*1);
    if (numEstiloActual!=0){
        numEstilo = numEstiloActual - 1;
        nombreEstilo ="tamano" + numEstilo;        
        setActiveStyleSheet(nombreEstilo, 1);
    }   
}
function estiloMas() {
    estiloActual = getActiveStyleSheet();
    numEstiloActual = (estiloActual.substring(6,7) * 1);
    if (numEstiloActual!=4){
        numEstilo = numEstiloActual + 1;
        nombreEstilo ="tamano" + numEstilo;        
        setActiveStyleSheet(nombreEstilo, 1);
    }
}
function abreventana(href){
    
    var features ='toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=no,copyhistory=no,width=790,height=590';
    window.open(href, 'nueva', features);
    //return false;
}