function numbersonly(myfield, e, dec, tariff)
{
	var key;
	var keychar;
	
	if (window.event)
	   key = window.event.keyCode;
	else if (e)
	   key = e.which;
	else
	   return true;
	keychar = String.fromCharCode(key);

	// control keys
	if ((key==10) || (key==13)) checkPrice(tariff);
	if ((key==null) || (key==0) || (key==8) || (key==9) || (key==13) || (key==27)) return true;

	else if ((("0123456789").indexOf(keychar) > -1))
	   return true;
	
   return false;
}

var http_request = false;
function checkPrice(tariff) {

	document.getElementById('calculated-price').innerHTML='Czekaj...';
	document.getElementById('destination').innerHTML='Czekaj...';	
	document.getElementById('calculated-price-2').innerHTML='';	

	var url;
	var user_number = document.getElementById('user-number').value;
	var destination = user_number;
	
	url = 'ajax_check_price.php?tariff=' + tariff + '&number=' + destination + '&rnd=' + Math.random(1000,9999999);
	
	http_request = false;
	if (window.XMLHttpRequest) { // Mozilla, Safari,...
	 http_request = new XMLHttpRequest();
	 if (http_request.overrideMimeType) {
		http_request.overrideMimeType('text/html');
	 }
	} else if (window.ActiveXObject) { // IE
	 try {
		http_request = new ActiveXObject("Msxml2.XMLHTTP");
	 } catch (e) {
		try {
		   http_request = new ActiveXObject("Microsoft.XMLHTTP");
		} catch (e) {}
	 }
	}
	if (!http_request) {
		alert('Blad: Twoja przegladarka nie obsluguje technologii AJAX');
		return false;
	}
	
	http_request.onreadystatechange = function() {
	  if (http_request.readyState == 4) {
		 if (http_request.status == 200) {
			if (http_request.responseText!='-1') {
				var response = http_request.responseText;
				var a = response.split(';');
				document.getElementById('calculated-price').innerHTML='<strong>'+a[0]+' zl/min.</strong>';
				document.getElementById('destination').innerHTML = a[1];
				c2=a[0].replace(',','.');
				c2=c2*1.22;
				c2=Math.round(c2*1000)/1000;	// zaokraglenie do dwóch miejsc po przecinku
				document.getElementById('calculated-price-2').innerHTML='<strong>('+c2+' zl/min. z VAT)</strong>';
			} else {
				document.getElementById('calculated-price').innerHTML='<strong>Numer nieprawidlowy</strong>';
				document.getElementById('calculated-price-2').innerHTML='';
				alert('Nieprawidlowy numer telefonu. Podaj numer w formacie identycznym jak podczas korzystania z normalnego telefonu.');
			}
		 }
	  }
	}
	
	http_request.open('GET', url, true);
	http_request.send(null);
}