var formChecker = {

	okColor			: '#CDEB8B',									// background to set when value is ok (textfield, textarea, select)
	nokColor		: '#73880A',	/* '#ea9b9b', */				// background to set when value is not ok	
	okTextColor		: '#000000',									// background to set when value is ok (checkbox/radiobutton)
	nokTextColor	: '#000000',	/* '#CF2639', */				// background to set when value is not ok (checkbox/radiobutton)
	nokMessage		: 'Gelieve alle vereiste velden in te vullen...',	// message to alert when form not ok, leave empty to not alert any message
	
	errorMsgSelect	: 'Kies een waarde',						// message to show on screen when select not ok
	errorMsgCheck	: 'Maak een keuze',						// message to show on screen when checkbox/radiobutton not ok
	errorMsgString	: 'Gelieve alle vereiste velden in te vullen.',					// message to show on screen when a textfield is empty
	errorMsgNumber	: 'Voer een nummer in',						// message to show on screen when no number was entered
	errorMsgEmail	: 'Voer een geldig e-mailadres in',			// message to show on screen when no e-mail was entered
	errorMsgUrl		: 'Voer een geldige url in',					// message to show on screen when no url was entered
	errorMsgDate	: 'Kies een datum',						// message to show on screen when no date was selected

	checkForm		: function (daForm) {
	
						var arClass, bValid, gotError;		  
						var objForm= daForm;
												
						var objField 	= formChecker._mergeNodeLists(
										  		objForm.getElementsByTagName('input'), 
										  		objForm.getElementsByTagName('textarea'), 
										  		objForm.getElementsByTagName('select')
										   ); 
						
						gotError = false;
						
						document.getElementById('formSubmit').disabled		= true;
						if (document.getElementById('spinner')) {
							document.getElementById('spinner').style.visibility	= 'visible';
						}
						
						for (var iFieldCounter=0; iFieldCounter<objField.length; iFieldCounter++) {
						
							// Allow for multiple values being assigned to the class attribute
							arClass = objField[iFieldCounter].className.split(' ');
							
							for (var iClassCounter=0; iClassCounter<arClass.length; iClassCounter++) {
								
								// console.debug("checking item '%s' with class '%s'", objField[iFieldCounter].name, arClass[iClassCounter]);
							
								switch (arClass[iClassCounter]) {
								
									case 'select':		      	
										bValid 		= formChecker._isSelected(objField[iFieldCounter]);
										errorMsg	= formChecker.errorMsgSelect;
										break;
									case 'check':		      	
										bValid 		= formChecker._isChecked(objField[iFieldCounter]);
										errorMsg	= formChecker.errorMsgCheck
										break;
									case 'email' :
										bValid 		= formChecker._isEmail(objField[iFieldCounter]);
										errorMsg	= formChecker.errorMsgEmail;
										break;
									case 'string':
										bValid 		= formChecker._isString(objField[iFieldCounter]);
										errorMsg	= formChecker.errorMsgString;
										break;
									case 'number' :
										bValid 		= formChecker._isNumber(objField[iFieldCounter]);
										errorMsg	= formChecker.errorMsgNumber;
										break;
									case 'url' :
										bValid 		= formChecker._isUrl(objField[iFieldCounter]);
										errorMsg	= formChecker.errorMsgUrl;
										break;
									case 'date' :
										bValid 		= formChecker._isDate(objField[iFieldCounter]);
										errorMsg	= formChecker.errorMsgDate;
										break;
									default:
										bValid = 'NULL';
										break;
									
								}
					
								if (bValid == false) {
					
									gotError = true;
									
									
									// date : color the label
									if (arClass[iClassCounter] == 'date') {
										document.getElementById('lbl_' + objField[iFieldCounter].id).style.backgroundColor = formChecker.nokColor;
									// checkboxes/radiobuttons : loop all checkboxes/radiobuttons
									} else if(arClass[iClassCounter] == 'check') {
										//var elems = document.getElementsByName(objField[iFieldCounter].name);
										//for (var i=0; i<elems.length; i++) {
										//	document.getElementById('lbl_' + elems[i].id).style.color = formChecker.nokTextColor;
										//}
									// normal : color the item
									} else {
										//objField[iFieldCounter].focus();
										objField[iFieldCounter].style.background = formChecker.nokColor;
									}
								
									// set errorMessage	
									if (document.getElementById("error_" + objField[iFieldCounter].name)) {
										document.getElementById("error_" + objField[iFieldCounter].name).innerHTML			= errorMsg;
										document.getElementById("error_" + objField[iFieldCounter].name).style.visibility	= 'visible';
									}
									
								} else {
									
									if (bValid != 'NULL') {	
									
										// date : color the label
										if (arClass[iClassCounter] == 'date') {
											document.getElementById('lbl_' + objField[iFieldCounter].id).style.backgroundColor = formChecker.okColor;
										// checkboxes/radiobuttons : loop all checkboxes/radiobuttons
										} else if(arClass[iClassCounter] == 'check') {
											//var elems = document.getElementsByName(objField[iFieldCounter].name);
											//for (var i=0; i<elems.length; i++) {
											//	document.getElementById('lbl_' + elems[i].id).style.color = formChecker.okTextColor;
											//}
										// normal : color the item
										} else {
											//objField[iFieldCounter].focus();
											objField[iFieldCounter].style.background = formChecker.okColor;
										}
										
										// unset errorMessage									
										if (document.getElementById("error_" + objField[iFieldCounter].name)) {
											document.getElementById("error_" + objField[iFieldCounter].name).innerHTML			= '';
											document.getElementById("error_" + objField[iFieldCounter].name).style.visibility	= 'hidden';
										}
									}	
									
								}
							}
						}
						
						if (gotError) {
							if (formChecker.nokMessage != '') {
								if (errorMsg != '') {
									alert(errorMsg);
								} else {
									alert(formChecker.nokMessage);	
								}
							}
							document.getElementById('formSubmit').disabled		= false;
							document.getElementById('spinner').style.visibility	= 'hidden';
							return false;
						} else {
							return true;
						}
					
	},
	
	_mergeNodeLists		: function (objInput, objTextarea, objSelect) {
	
							var objField = new Array();
							
							if (objInput.length != 0) {
								for (i = 0; i < objInput.length; i++) {
									objField[i]	= objInput.item(i);	
								}
							}
							
							if (objTextarea.length != 0) {
								for (i = 0; i < objTextarea.length; i++) {
									objField[objInput.length + i]	= objTextarea.item(i);	
								}
							}
							
							if (objSelect.length != 0) {
								for (i = 0; i < objSelect.length; i++) {
									objField[objInput.length + objTextarea.length + i]	= objSelect.item(i);	
								}
							}	
							
							return objField;
	},
	
	_isOptional			: function(className) {
							var re = new RegExp("optional");
							var m = re.exec(className);
							if (m == null) {
								return false;
							} else {
								return true;
							}
	},
		
	_isSelected			: function (objField) {
							if (formChecker._isOptional(objField.className) && (objField.selectedIndex == 0)) {
								return true;
							} else {
								if (objField.selectedIndex == 0) {
									return false;
								} else {
									return true;
								}
							}
	},
	
	_isChecked			: function (objField) {
							var arrOptions = document.getElementsByName(objField.name);
							for (var i=0; i<arrOptions.length; i++) {
								if (arrOptions[i].checked) return true;
							}
							return false;
	},
		
	_isString			: function (objField) {
							strValue	= objField.value.replace(/^\s*|\s*$/g, '');
							if (formChecker._isOptional(objField.className) && (strValue == "")) {
								return true;
							} else {
								return (typeof strValue == 'string' && strValue != ''); //  && isNaN(strValue)
							}
	},
		
	_isNumber			: function (objField) {
							strValue	= objField.value;
							if (formChecker._isOptional(objField.className) && (strValue == "")) {
								return true;
							} else {
								return (!isNaN(strValue) && strValue != '');
							}
	},
		
	_isEmail			: function (objField) {
							strValue	= objField.value;
							if (formChecker._isOptional(objField.className) && (strValue == "")) {
								return true;
							} else {
								var objRE = /^[\w-\.\']{1,}\@([\da-zA-Z-]{1,}\.){1,}[\da-zA-Z-]{2,}$/;
								return (strValue != '' && objRE.test(strValue));
							}
	},
	
	_isUrl				: function (objField) {	
							strValue	= objField.value;
							if (formChecker._isOptional(objField.className) && (strValue == "")) {
								return true;
							} else {
								var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/
								return regexp.test(strValue);
							}	
	},
	
	_isDate				: function (objField) {
							strValue	= objField.value;
							if (formChecker._isOptional(objField.className) && (strValue == "")) {
								return true;
							} else {
								//return !isNaN(new Date(strValue));		// <<--- this needs checking
								return formChecker._isString(objField);
							}
	}
}