function showRegistration() {
	document.getElementById('registrationblock').style.display='block';
}

function hideRegistration() {
	document.getElementById('registrationblock').style.display='none';
}

function checkData_loginform(){
	var correct = true
	var regexpemail =/^[a-zA-Z0-9\-\.\_]+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,3}|[0-9]{1,3})(\]?)$/; //regexp for e-mail address
	var str = document.loginform.username.value; // value to compare
	if (regexpemail.test(str) == false){
	correct = false; alert("Vul uw e-mailadres in.");document.loginform.username.focus(); return correct}
	if (document.loginform.password.value == '') {correct = false; alert("Vul uw toegangscode in.");document.loginform.password.focus(); return correct}
	return correct;
}

// POPUP SCRIPT

var win = null;

function openPopup(theURL,winName,w,h){
	LeftPosition = (screen.width) ? (screen.width-w)/2 : 0;
	TopPosition = (screen.height) ? (screen.height-h)/2 : 0;
	settings ='height='+h+',width='+w+',top='+TopPosition+',left='+LeftPosition+',scrollbars=no, resizable=no'
	win = window.open(theURL,winName,settings)
}