function formCheck(formobj){ 

	// Enter name of mandatory fields
	var fieldRequired = Array("k1", "k2", "k3", "k4", "k5", "k6", "k7", "k8", "k9", "k10");
	// Enter field description to appear in the dialog box
	var fieldDescription = Array("Język", "Miasto", "Preferowane dni tygodnia","Preferowane godziny","Czas trwania jednego spotkania","Obecny poziom znajomosci języka","Rodzaj zajęć","Imię i nazwisko","E-mail","Telefon kontaktowy");
	// dialog message
	var alertMsg = "Wpisz wszystkie wymagane pola:\n\n";
	
	var l_Msg = alertMsg.length;
	
	for (var i = 0; i < fieldRequired.length; i++){
		var obj = formobj.elements[fieldRequired[i]];
		if (obj){
			switch(obj.type){
			case "select-one":
				if (obj.selectedIndex == -1 || obj.options[obj.selectedIndex].text == ""){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			case "select-multiple":
				if (obj.selectedIndex == -1){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			case "text":
			case "textarea":
				if (obj.value == "" || obj.value == null){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
				break;
			default:
			}
			if (obj.type == undefined){
				var blnchecked = false;
				for (var j = 0; j < obj.length; j++){
					if (obj[j].checked){
						blnchecked = true;
					}
				}
				if (!blnchecked){
					alertMsg += " - " + fieldDescription[i] + "\n";
				}
			}
		}
	}

	if (alertMsg.length == l_Msg){
		return true;
	}else{
		alert(alertMsg);
		return false;
	}
}