function xGetElementById(e) {
    if(typeof(e)!='string') return e;
    if(document.getElementById) e=document.getElementById(e);
    else if(document.all) e=document.all[e];
    else e=null;
    return e;
}

function trim(value) {
	value = value.replace(/^\s+/,''); 
	value = value.replace(/\s+$/,'');
	return value;
}

function jFocus(elm) {
    if(typeof(elm) == 'string') {
        elm = xGetElementById(elm);
    }
    if (elm) {      
        elm.focus();
        elm.select();
    }
}

function echeck(str) {
	var at="@"
	var dot="."
	var lat=str.indexOf(at)
	var lstr=str.length
	var ldot=str.indexOf(dot)
	if (str.indexOf(at)==-1){
	   return false
	}

	if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
	   return false
	}

	if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		return false
	}

	 if (str.indexOf(at,(lat+1))!=-1){
		return false
	 }

	 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		return false
	 }

	 if (str.indexOf(dot,(lat+2))==-1){
		return false
	 }
	
	 if (str.indexOf(" ")!=-1){
		return false
	 }

	 return true					
}

function checkContactForm() {
	var strNaam = trim(document.forms[0].naam.value);
	var strEmail = (document.forms[0].email.value);
	var strVraag = (document.forms[0].vraag.value);
	
	if (strNaam.length == 0) {
		window.alert("Vul alstublieft uw naam in.");
		jFocus("naam")
		return false;
	}
	
	if (strEmail.length == 0) {
		window.alert("Vul alstublieft uw e-mail adres in.");
		jFocus("email");
		return false;
	} else {
		if (!echeck(strEmail)) {
			window.alert("Het opgegeven e-mail adres is geen geldig e-mail adres.");
			jFocus("email");
			return false;
		}
	}
	
	if (strVraag.length == 0) {
		window.alert("Vul alstublieft uw vraag of opmerking in.");
		jFocus("vraag");
		return false;
	}
	
	return true;
}

function checkContactFormEnglish() {
	var strNaam = trim(document.forms[0].naam.value);
	var strEmail = (document.forms[0].email.value);
	var strVraag = (document.forms[0].vraag.value);
	
	if (strNaam.length == 0) {
		window.alert("Please enter your name.");
		jFocus("naam")
		return false;
	}
	
	if (strEmail.length == 0) {
		window.alert("Please enter your e-mail address.");
		jFocus("email");
		return false;
	} else {
		if (!echeck(strEmail)) {
			window.alert("The entered e-mail address is not a valid e-mail address.");
			jFocus("email");
			return false;
		}
	}
	
	if (strVraag.length == 0) {
		window.alert("Please enter your questions or comment.");
		jFocus("vraag");
		return false;
	}
	
	return true;
}