function getElement(id){
    var element = document.getElementById(id);

    return (element != null && element != undefined) ? element : false;
}

function show(id) {
    var element = getElement(id);
    
    if( element ){
        element.style.display = 'block';
    }
}

function hidden(id) {
    var element = getElement(id);

    if( element ){
        element.style.display = 'none';
    }
}

function sendBuy(code,url) {    
    var select = getElement('select-extra-item-' + code);
    if (select) {
        url = url + "&e=" + select.options[select.selectedIndex].value;
    }else {
        select = getElement('select-extra-ofertas-item-' + code);
        if (select) {
            url = url + "&e=" + select.options[select.selectedIndex].value;
        }
    }
    
    sendAjax(url, 'shopping-cart');
    hidden('select-extra-' + code);
    hidden('select-extra-oferta-' + code);
    show('link-shopping-cart-' + code);
}
    
function change_link (id_link,url){
    var link = document.getElementById(id_link);
    link.href = url;
}

function newAjax(){
    var xmlhttp=false;
    try {
        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
        try {
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (E) {
            xmlhttp = false;
        }
    }

    if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
        xmlhttp = new XMLHttpRequest();
    }
    return xmlhttp;
}

function sendPost(url,id_container,post){
    var container;
    container = document.getElementById(id_container);
    ajax=newAjax();
    ajax.open("POST", url,true);
    ajax.onreadystatechange=function() {
        if (ajax.readyState==4 && container != undefined && container != null) {
            container.innerHTML = ajax.responseText;
        }
    }
    ajax.send(post);
}

function sendGet(url,id_container){
    sendAjax(url,id_container);
}

function sendAjax(url,id_container){
    var container;
    container = document.getElementById(id_container);
    ajax=newAjax();
    ajax.open("GET", url,true);
    ajax.onreadystatechange=function() {
        if (ajax.readyState==4 && container != undefined && container != null) {
            container.innerHTML = ajax.responseText
        }
    }
    ajax.send(null)
}