function tarkistaArvontaLomake() {
	var f = document.forms['arvontalomake'];
	var error = 0;
	
	document.getElementById('yritys').style.background = "white";
	document.getElementById('nimi').style.background = "white";
	document.getElementById('sahkoposti').style.background = "white";
	document.getElementById('puhelin').style.background = "white";
	
	document.getElementById('yritys').style.color = "#0078ba";
	document.getElementById('nimi').style.color = "#0078ba";
	document.getElementById('sahkoposti').style.color = "#0078ba";
	document.getElementById('puhelin').style.color = "#0078ba";
	
	document.getElementById('error').innerHTML = ' ';
	
	if( f.yritys.value == '' ) {
		error++;
		document.getElementById('yritys').style.background = "#f20020";
		document.getElementById('yritys').style.color = "#ffffff";
	}
	
	if( f.nimi.value == '' ) {
		error++;
		document.getElementById('nimi').style.background = "#f20020";
		document.getElementById('nimi').style.color = "#ffffff";
	}
	
	if( f.sahkoposti.value == '' ) {
		error++;
		document.getElementById('sahkoposti').style.background = "#f20020";
		document.getElementById('sahkoposti').style.color = "#ffffff";
	}
	
		if( f.puhelin.value == '' ) {
		error++;
		document.getElementById('puhelin').style.background = "#f20020";
		document.getElementById('puhelin').style.color = "#ffffff";
	}

	
	if( error > 0 ) {
		document.getElementById('error').innerHTML = 'Täytä puuttuvat kohdat.';
		return false;
	}
	else return true;
	
}