function getCheckedRadioValue(oRadio) 
{
	if(!oRadio)
		return "";
	var iLength = oRadio.length;

	if(iLength == undefined)
		if(oRadio.checked)
			return oRadio.value;
		else
			return "";
	for(var i = 0; i < iLength; i++) 
	{
		if(oRadio[i].checked) 
		{
			return oRadio[i].value;
		}
	}
	return "";
}



function navigation_down(elem) {
	object = document.getElementById(elem);
	object.scrollTop += 20;
}

function navigation_up(elem) {
	object = document.getElementById(elem);
	object.scrollTop -= 20;
}

function checkEmail(value) {
	if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(value)){
		return (true)
	}
	return (false)
}
	
function validateForm() {
	fromEmail = document.getElementById('fromEmail');
	toEmail = document.getElementById('toEmail');
	fromName = document.getElementById('fromName');
	toName = document.getElementById('toName');
	
	if (!checkEmail(fromEmail.value)){
		errormsg('Jouw emailadres is niet juist');
		return false;
	}
	
	if (!checkEmail(toEmail.value)){
		errormsg('Je vriends emailadres is niet juist');
		return false;
	}
	
	if (fromName.value=='') {
		errormsg('Jouw naam is niet ingevuld');
		return false;
	}
	
	if (toName.value=='') {
		errormsg('Je vriends naam is niet ingevuld');
		return false;
	}
}

function errormsg(value)
{
	msg = document.getElementById('errormsg');
	msg.innerHTML = value + "<br/><br/>";
}

function setFrameUrl( sFrameID, sUrl )
{
	if ( document.getElementById )
	{			
		var oFrame = document.getElementById( sFrameID );
		if ( oFrame )
			oFrame.src = sUrl;
	}
	else if ( window.frames && window.frames[ sFrameID ] && sUrl )
	{
		window.frames[ sFrameID ].location.replace( sUrl );
	}
}

// geef een frame een nieuwe url
function getFrameUrl( sFrameID )
{
	if ( document.getElementById )
	{			
		var oFrame = document.getElementById( sFrameID );
		if ( oFrame )
			return oFrame.src;
	}
	else if ( window.frames && window.frames[ sFrameID ] )
	{
		return window.frames[ sFrameID ].location;
	}
}