function validate(f)
{
	var strMessage = '';
	var objTemp;
	var radiofalsearray = [];
	var radiotruearray = [];
	var radioarray = [];
	for ( var i = 0; i < f.elements.length; i++ ) {
		objTemp = f.elements[i];
		strName = objTemp.name
		if ( strName.substr( strName.length - 9 ) == '_required' ) {
			strName = strName.replace( /_required/, '' );
			strName = strName.replace( /_/g, ' ' );
			strName = strName.toLowerCase();
			if ( objTemp.value == '' ) {
				boolIsValid = false;
				strMessage += '-' + strName + ' is leeg\r\n';
			} else if ( objTemp.type == 'radio' ) {
				if ( objTemp.checked ) {
					radiotruearray.push(strName)
  				}else{
					found = false
					for ( var j = 0; j < radiofalsearray.length; j++ ) {
						if (radiofalsearray[j] == strName) {
							found = true;
							break;
						}
					}

					if(!found) {
						radiofalsearray.push(strName)
					}
				}
			}
		}
	}
	for ( var j = 0; j < radiofalsearray.length; j++ ) {
		boolIsValid = false;
		objTemp = radiofalsearray[j]
		for  ( var k = 0; k < radiotruearray.length; k++ ) {
			if (radiotruearray[k] == objTemp) {
				boolIsValid = true
				break;
			}
		}
		if (!boolIsValid ) {
			strMessage += '-' + objTemp + ' is niet geselecteerd\r\n';
		}
	}
	if (strMessage != '') {
		strMessage = 'De volgende velden zijn niet correct: \r\n' + strMessage
		alert(strMessage)
		return false
	}
}