function validate_naam(){
	input_value = document.getElementById('naam').value.length;
    if (input_value != 1 & input_value != 0){
       document.getElementById('imgNaam').src='http://www.brixmakelaars.nl/images/ok.jpg';
       counter1=1;
    } else {
       document.getElementById('imgNaam').src='http://www.brixmakelaars.nl/images/empty.jpg';
       counter1=0;
    }
    if(counter1 == 1 & counter2 == 1 & counter3 == 1){
        document.getElementById('submit').disabled = false;
   	} else {
       	document.getElementById('submit').disabled = true;
	}
}

function validate_telefoon(){
	input_value = document.getElementById('telefoon').value.length;
    if (input_value != 1 & input_value != 0){
       document.getElementById('imgTelefoon').src='http://www.brixmakelaars.nl/images/ok.jpg';
       counter2=1;
    } else {
       document.getElementById('imgTelefoon').src='http://www.brixmakelaars.nl/images/empty.jpg';
       counter2=0;
    }
    if(counter1 == 1 & counter2 == 1 & counter3 == 1){
        document.getElementById('submit').disabled = false;
   	} else {
       	document.getElementById('submit').disabled = true;
	}
}

function validate_email(){
	input_value = document.getElementById('email').value.length;
    if (input_value != 1 & input_value != 0){
       document.getElementById('imgEmail').src='http://www.brixmakelaars.nl/images/ok.jpg';
       counter3=1;
    } else {
       document.getElementById('imgEmail').src='http://www.brixmakelaars.nl/images/empty.jpg';
       counter3=0;
    }
    if(counter1 == 1 & counter2 == 1 & counter3 == 1){
        document.getElementById('submit').disabled = false;
   	} else {
       	document.getElementById('submit').disabled = true;
	}
}

function validate_koophuur(){
	input_value = document.getElementById('koophuur').value;	
	if (input_value=='Koop') {
		document.getElementById('koop1').style.display='table-row'; 
		document.getElementById('koop2').style.display='table-row'; 
		document.getElementById('huur1').style.display='none'; 
		document.getElementById('huur2').style.display='none'; 
	}
	else if (input_value=='Huur') {
		document.getElementById('koop1').style.display='none'; 
		document.getElementById('koop2').style.display='none'; 
		document.getElementById('huur1').style.display='table-row'; 
		document.getElementById('huur2').style.display='table-row'; 
	}
	else if (input_value=='Geen voorkeur') {
		document.getElementById('koop1').style.display='table-row'; 
		document.getElementById('koop2').style.display='table-row'; 
		document.getElementById('huur1').style.display='table-row'; 
		document.getElementById('huur2').style.display='table-row'; 
	}
	else {
		document.getElementById('koop1').style.display='none'; 
		document.getElementById('koop2').style.display='none'; 
		document.getElementById('huur1').style.display='none'; 
		document.getElementById('huur2').style.display='none';
		
	}
}