function gebid(id){
	return document.getElementById(id);
}

function ec(str){
	return encodeURIComponent(str);	
}

function ajax(url,vars,callbackFunction){

	if(window.XMLHttpRequest){
		var request = new XMLHttpRequest();
	} 
	else{
		var request = new ActiveXObject('MSXML2.XMLHTTP.3.0');
	}

	request.open('POST',url,true);
	request.setRequestHeader('Content-Type','application/x-www-form-urlencoded');

	request.onreadystatechange = function(){
		if(request.readyState == 4 && request.status == 200){
			if(request.responseText){
				callbackFunction(request.responseText);
			}
		}
	}
	request.send(vars);
}

function contact(){
	var poststr 			= "naam="+ec(gebid('naam').value)+"&e-mailadres="+ec(gebid('e-mailadres').value)+"&bericht="+ec(gebid('bericht').value)+"&letters="+ec(gebid('letters').value);
	gebid('submit').innerHTML 	= 'Moment';
	gebid('submit').disabled 	= true;
	ajax('inc/ajax.php?soort=contact',poststr,ok_letters);
}

function ok_letters(result){

	var result_out 		= result.split("|");

	var result_mess		= result_out[0]; 
	var result_id		= result_out[1]; 

	if( result_mess == 'OK' ){
		gebid('formulier').style.display 	= 'none';
		gebid('verzonden').innerHTML		=  result_id;
		gebid('verzonden').style.display 	= 'block';
	}
	else{

		if( result_id == 'letters'){
   			img 				= gebid('img_letters'); 
   			img.src 			= 'inc/letters.php?' + Math.random();
			gebid('letters').value		= '';
		}

		alert(result_mess);
		gebid(result_id).focus();
		gebid('submit').innerHTML 		= 'Verstuur';
		gebid('submit').disabled 		= false;
	}
}