function checkform() {

	//// required objects defineren
	a = new Array();
	a[0] = Array("naam","Naam","string");
	a[1] = Array("telefoon","Telefoon","string");
	a[2] = Array("email","E-mail adres","string");
	a[3] = Array("vraag","Vraag/opmerking","string");

	
	//// Required fiels check
	for(i=0;i<a.length;i++) {

		if(requiredfield(document.getElementById(a[i][0]),a[i][1],a[i][2])==false) {
			return;
		}	
	}
	document.contact.submit();
}

function checkmailinglist() {


	a = new Array();
	a[0] = Array("naam","Naam","string");
	a[1] = Array("email","E-mail adres","string");

	//// Required fiels check
	for(i=0;i<a.length;i++) {

		if(requiredfield(document.getElementById(a[i][0]),a[i][1],a[i][2])==false) {
			return;
		}	
	}
	document.mailinglist.submit();
}

function checkzoekopdracht() {


	a = new Array();
	a[0] = Array("naam","Naam","string");
	a[1] = Array("email","E-mail adres","string");
	a[2] = Array("minprijs","Minimum prijs","integer");
	a[3] = Array("maxprijs","Maximum prijs","integer");

	//// Required fiels check
	for(i=0;i<a.length;i++) {

		if(requiredfield(document.getElementById(a[i][0]),a[i][1],a[i][2],a[i][3])==false) {
			return;
		}	
	}
	document.zoekopdracht.submit();
}

function checkzoekopdracht_unsubscribe() {

	a = new Array();
	a[0] = Array("email","E-mail adres","string");

	//// Required fiels check
	for(i=0;i<a.length;i++) {

		if(requiredfield(document.getElementById(a[i][0]))==false) {
			return;
		}	
	}
	document.zoekopdracht_unsubscribe.submit();
}

//Checks a field for values
function requiredfield(strfield,message,type)
{
		if(strfield.value == "") {
			alert(message + " is niet opgegeven!");
			strfield.focus();
			return false;
		}
		
	//extra check voor integer
	if(type == "integer") {
		
		if (checknumbers(strfield) == false) {
			
			alert(message + ": er morgen alleen cijfers worden opgegeven!");
			strfield.focus();
			return false;
		}
		else {
				return true;
		}
	}
	
		return true;

	
}
	
function checknumbers(strfield){

		len = strfield.value.length;
		if(len!=0){
			for (x=0; x<len; x++) {
			
				nbr = strfield.value.substring(x,x+1);
				if(!isNaN(nbr)) { 
				}
				else {	
					if (nbr == "." || nbr == ",") {
						//Deze tekens worden allemaal toegestaan...
					}
					else {
						return false;
					}
				}
			}
		}//if len
		return true;
}