//object constructor
	function formValidator(formname,debug){
	//properties
		this.debug = debug? true:false;
		this.formname = formname;
		this.commandQueue = new Array();
		this.commandItemCount = 0;
	}

//prototype
	//internal helper functions
		formValidator.prototype.errorHandling = errorHandling;
		formValidator.prototype.addCommandQueueItem = addCommandQueueItem;
		formValidator.prototype.execCommandQueueItem = execCommandQueueItem;
		formValidator.prototype.checkForm = checkForm;
		
	//functions
		formValidator.prototype.textboxEmpty = textboxEmpty;	
		formValidator.prototype.textboxEmptyF = textboxEmptyF;	
		formValidator.prototype.textboxEmail = textboxEmail;	
		formValidator.prototype.textboxEmailF = textboxEmailF;
		formValidator.prototype.radioChecked = radioChecked;	
		formValidator.prototype.radioCheckedF = radioCheckedF;
		formValidator.prototype.checkboxChecked = checkboxChecked;	
		formValidator.prototype.dropdownSelected = dropdownSelected;
		formValidator.prototype.dropdownSelectedF = dropdownSelectedF;
		formValidator.prototype.compareValues = compareValues;
		formValidator.prototype.compareValuesF = compareValuesF;
		formValidator.prototype.characterCheck = characterCheck;
		formValidator.prototype.characterCheckF = characterCheckF;
		formValidator.prototype.fieldLength = fieldLength;
		formValidator.prototype.fieldLengthF = fieldLengthF;
		

//implementation
	
	//internal helper functions
		function errorHandling(message){
			alert(message);
			//document.forms[this.formname].onsubmit='return false';
			return true; 
		}
		
		function execCommandQueueItem(queueItem){
			return this.commandQueue[queueItem][0](this.commandQueue[queueItem][1]);
		}
		
		function addCommandQueueItem(functionname,parameterlist){
			this.commandQueue[this.commandItemCount] = new Array(functionname,parameterlist); // parameterlist is an array
			this.commandItemCount++;
		}
		
		function checkForm(){
			this.debug ? window.onerror = this.errorHandling:void(0);
			for(var i = 0;i<this.commandItemCount;i++){
				if(!this.execCommandQueueItem(i)){this.debug ? window.onerror = null : void(0);return false;}
			}
			this.debug ? window.onerror = null : void(0);
			return true;
		}
	//functions
		/****************** TextboxEmpty ******************/
		function textboxEmpty(formname,formItemName,errorMsg,defaultText){
			this.addCommandQueueItem(this.textboxEmptyF,arguments);
		}
		
		function textboxEmptyF(params){//formname,formItemName,errorMsg,defaultText
			var formname=params[0],formItemName=params[1],errorMsg=params[2],defaultText=params[3];
			if(defaultText='undefined'){
				defaultText='';
			}
			var strValue = document.forms[formname].elements[formItemName].value.length>0 && document.forms[formname].elements[formItemName].value!=defaultText;
			if (! strValue){	
				alert(errorMsg);
				document.forms[formname].elements[formItemName].focus();
				return false;
			}
			else{
				return true;
			}
		}
		
		/****************** TextboxEmail ******************/
		function textboxEmail(formname,formItemName,errorMsg){	
			this.addCommandQueueItem(this.textboxEmailF,arguments);
		}

		function textboxEmailF(params){
			var formname=params[0],formItemName = params[1],errorMsg = params[2];
			var strValue = document.forms[formname].elements[formItemName].value;
			if (! strValue.match(/^[\w]{1}[\w\.\-_]*@[\w]{1}[\w\-_\.]*\.[\w]{2,6}$/i)) {	
				alert(errorMsg);
				document.forms[formname].elements[formItemName].focus();
				return false;
			}else{
				return true
			}
		}
		
		/****************** RadioChecked ******************/
		function radioChecked(formName,formItemName,errorMsg){
			this.addCommandQueueItem(this.radioCheckedF,arguments);
		}
		
		function radioCheckedF(params){//formName,formItemName,errorMsg 
               var field = document.forms[params[0]].elements[params[1]]; 
               if (!field.length){ 
                   	if(field.checked){
				   		return true;
					}
					else{
						 alert(params[2]);
						 return false;
					}
               } 
               for(var i = 0; i < field.length; i++){if(field[i].checked) return true;} 
               alert(params[2]); 
               return false; 
          }
		
		/****************** CheckboxChecked ******************/
		function checkboxChecked(formName,formItemName,errorMsg){
			this.addCommandQueueItem(this.radioCheckedF,arguments);
		}
		
	
		/****************** DropdownSelected ******************/
		function dropdownSelected(formName,formItemName,errorMsg){
			this.addCommandQueueItem(this.dropdownSelectedF,arguments);
		}
		
		function dropdownSelectedF(params){//formName,formItemName,errorMsg
			var field = document.forms[params[0]].elements[params[1]];
			if(field.selectedIndex==0){
				alert(params[2]);
				field.focus();
				return false;
			}
			return true;
		}
		
		/****************** compareValues ******************/
		function compareValues(formName,formItemName1,formItemName2,errorMsg){
			this.addCommandQueueItem(this.compareValuesF,arguments);
		}
		
		function compareValuesF(params){ //formName,formItemName1,formItemName2,errorMsg,resetfields;
			if(!(document.forms[params[0]].elements[params[1]].value == document.forms[params[0]].elements[params[2]].value)){
				alert(params[3]);
				if(params[4]){
					document.forms[params[0]].elements[params[1]].value ='';
					document.forms[params[0]].elements[params[2]].value ='';
				}
				document.forms[params[0]].elements[params[1]].focus();
				return false;
			}
			return true;
		}
		/****************** characterCheck ******************/
		function characterCheck(formName,formItemName1,validCharacterList,errorMsg)
		{
		    this.addCommandQueueItem(this.characterCheckF,arguments);
		}
		
		function characterCheckF(param)//formName,formItemName,validCharacterList,errorMsg
		{
		    var chars = param[2];
			var formFieldvalue = document.forms[param[0]].elements[param[1]].value;
			for (var i = 0; i < formFieldvalue.length; i++)
			{
				if (chars.indexOf(formFieldvalue.charAt(i)) == -1)
				{
					alert(param[3]);
					document.forms[param[0]].elements[param[1]].focus();
					return false;
				}
			}
			return true;
		}
		
		function fieldLength(formName,formItemName1,fromlength,tolength,errorMsg)
		{
		    this.addCommandQueueItem(this.fieldLengthF,arguments);
		}
		
		function fieldLengthF(param)//formName,formItemName,fromlength,tolength,errorMsg
		{
		  
			var formFieldvalue = document.forms[param[0]].elements[param[1]].value;
			if(param[2]< formFieldvalue.length || param[3]> formFieldvalue.length){
				alert(param[4]);
				document.forms[param[0]].elements[param[1]].focus();
				return false;
			}
			return true;
		}