function checkForm(obj)
{
	var i;
	var empty;
	var checks= new Array();
	checks[0] = 'naam';
	checks[1] = 'email';
	checks[2] = 'vraag';
	
	empty = false;
	for(i = 0; i < checks.length; i++)
	{
		if(!checkEmpty(checks[i]))
		{
			changeStyle(checks[i],true);
			empty = true;
		}
		else
		{
			changeStyle(checks[i],false);
		}
	}
	if(empty == true)
	{
		return false;	
	}
	else
	{
		return true;	
	}
}



function changeStyle(idName,bool)
{
	if(bool == true)
	{
		document.getElementById(idName).style.background = 'red';
		document.getElementById(idName).style.color = 'white';
	}
	else
	{
		document.getElementById(idName).style.background = 'white';
		document.getElementById(idName).style.color = 'black';
	}
	return;
	
}

function checkEmpty(idName)
{
	if(trim(document.getElementById(idName).value) == '')
	{
		return false;
	}
	else
	{
		return true;
	}
}
function trim(value) {
  value = value.replace(/^\s+/,'');
  value = value.replace(/\s+$/,'');
  return value;
}
document.write('<form id="contact" method="post" onsubmit="return checkForm(this);" action=""><label for="naam">Uw naam</label><input name="naam" type="text" id="naam" size="30" class="boxes"/><br/><label for="email">Uw e-mailadres:</label><input name="email" type="text" id="email" size="30" class="boxes"/><br/><label for="vraag">Vragen/Opmerkingen:</label><textarea name="vraag" cols="30" rows="5" id="vraag" class="boxes"></textarea><br/><input type="submit" id="btn" value="Verzend" class="submit"></form>');