function fnCheck(){
	if(!document.frmMain.txtEmail.value){
		alert('Vul uw e-mailadres in.');
		document.frmMain.txtEmail.focus();
		return false;
	}
	else if(!validateEmail(document.frmMain.txtEmail.value)){
		alert('Uw e-mailadres is niet juist.');
		document.frmMain.txtEmail.select();
		return false;
	}
	else{
		document.frmMain.cmdSubmit.disabled = true;
		document.frmMain.submit();
	}
}

function validateEmail(str) {
    var filter = /^[\w~][\w\.\-~]*[\w~]@[\w~][\w\-~]*[\.][\w~][\w\.\-~]*[\w]$|^$/;
    return filter.test(str);
}