var my_elem = document.getElementById('product-availability');

async function czytajcene(file)
{
    var rawFile = new XMLHttpRequest();
    rawFile.open("GET", file);
    rawFile.onreadystatechange = function ()
    {
        if(rawFile.readyState === 4)
        {
            if(rawFile.status === 200 || rawFile.status == 0) if(rawFile.responseText.length != 0)
            {
            var elem = document.createElement('div');
			elem.style = 'padding: 10px 0 0';
                elem.innerHTML = 'Najniższa cena z 30 dni: '+rawFile.responseText;
            my_elem.parentNode.insertBefore(elem, my_elem.nextSibling);

            }
        }
    }
    rawFile.send(null);
}

function check_omnibus() {
	var u = window.location.hostname+window.location.pathname;
	var cena = document.querySelector('.current-price span').innerText;
	czytajcene('/omnibus/?produkt='+encodeURIComponent(u)+'&cena='+encodeURIComponent(cena));
}
if( document.querySelector('.current-price span') ) check_omnibus();