// ppk's addeventsimple
function addEventSimple(obj,evt,fn) {
	if (obj.addEventListener)
		obj.addEventListener(evt,fn,false);
	else if (obj.attachEvent)
		obj.attachEvent('on'+evt,fn);
}

// hide fields that are not needed at first
function hideFormFields() {
		if (!document.getElementById('ander')) {
		return;
		}
		else {
			// hide that field
			document.getElementById('ander').style.display = "none";
		}
}
// function for the select list on change handler
function setSelectChange() {
		if (!document.getElementById('soort')) {
		return;
		}
		else {
			var selectOnChange = document.getElementById('soort'); 
        	selectOnChange.onchange = function() {
				// put the selected text/value in a variable
				var selectedoption = selectOnChange.options[selectOnChange.selectedIndex].text;
				//alert(selectOnChange.options[selectOnChange.selectedIndex].text);
				if (selectedoption == "Andere") {
					//alert("yes");
					document.getElementById('ander').style.display = "block";
					document.getElementById('field-merk').style.display = "block";
					document.getElementById('field-type').style.display = "block";
					document.getElementById('select-bouwjaar').style.display = "block";
				} 
				else if (selectedoption == "Sympathisant") {
					document.getElementById('field-merk').style.display = "none";
					document.getElementById('field-type').style.display = "none";
					document.getElementById('select-bouwjaar').style.display = "none";
					document.getElementById('ander').style.display = "none";
				}
				else {
					document.getElementById('ander').style.display = "none";
					document.getElementById('field-merk').style.display = "block";
					document.getElementById('field-type').style.display = "block";
					document.getElementById('select-bouwjaar').style.display = "block";
				}
			}
		}
}
// initialize functions
addEventSimple(window,'load',hideFormFields);
addEventSimple(window,'load',setSelectChange);