function Form() {
	this.form=null;
	//this.tooltip_name=null;
	//this.error_message=[];
	this.error_object=[];
	this.error_message_id=null;
	this.error_box_id=null;
	this.invalid_color="#ffe8e8";
	this.valid_color="#ffffff";
	this.invalid_text_color="red";
}

Form.prototype = {
	setForm: function(f) {
		this.form=f;
	},
	setErrorMessageID: function (id) {
		this.error_message_id=id;
	},
	setErrorBoxID: function (id) {
		this.error_box_id=id;
	},
	setElementErorrBox: function(e, show) {
		var error_id=e.getAttribute("error_message_id")
		var message=e.getAttribute("error_message")
		var error_box=document.getElementById(error_id);
		if (show) {
			e.style.background=this.invalid_color;
			if (error_id!=null && message!=null) {
				if (error_box!=null) {
					error_box.innerHTML=message;
					error_box.style.color=this.invalid_text_color;
				}
			}
		} else {
			e.style.background=this.valid_color;
			if (error_box!=null) {
				error_box.innerHTML="";
			}
		}
	},
	getErrorCount: function() {
		return this.error_object.length;
	},
	showElementsErrorMessage: function() { /* show individual elements' error message into individual id box */
		var i, o, error_box, error_id,message;
		
		for (i=0; i<this.error_object.length; i++) {
			o=this.error_object[i];
			this.setElementErorrBox(o, true);
		}
		
	},
	showErrorMessage: function() {
		var box=document.getElementById(this.error_box_id);
		var message=document.getElementById(this.error_message_id);
		var i;
		var error_message=[];
		
		for (i=0; i<this.error_object.length; i++) {
			error_message[error_message.length]=this.error_object[i].title;	//title should not be used, because it is used by browser to show tooltips
			this.error_object[i].style.background=this.invalid_color;
		}
		
		message.innerHTML=error_message.join("<br>");
		box.style.display="";
	},
	hideErrorMessage: function() {
		var box=document.getElementById(this.error_box_id);
		//var message=document.getElementById(this.error_message_id);
		//message.innerHTML=this.error_message.join("<br>");
		box.style.display="none";
	},
	validateAllInput: function() {
		var e, i, check, j;
		//var elements=this.form.getElementsByTagName("input");
		var elements=this.form;
		check=true;
		var error_object=[];
		for (i=0; i<elements.length; i++) {
			e=elements[i];

			if (e.getAttribute("check")!=null) {
				if (this.validateInput(e)==false) {
					//error_message[error_message.length]=e.title;
					error_object[error_object.length]=e;
					//bgcolor=this.invalid_color;
					check=false;
				}
				e.style.background=this.valid_color;
				this.setElementErorrBox(e, false);
			}
		}
		
		//this.error_message=error_message;
		this.error_object=error_object;
		
		return check;
	},
	validateInput: function(element) {
		var check, valid;
		var e=element;
		var bgcolor;
		var result=true;
		var check_string=element.getAttribute("check");
		var parameters;
		if (check_string!=null) {	//perform checking
			check=check_string.split("|");
			for (j=0; j<check.length; j++) {
				parameters=check[j].split(":");
				valid=true;
				if (parameters[0]=="email") {
					valid=this.isValidEmailFormat(e);
				} else if (parameters[0]=="blank") {
					valid=this.isBlank(e);
					valid=!valid;
				} else if (parameters[0]=="min_char") {
					valid=this.isMinimumCharacter(e, parameters[1]);
				} else if (parameters[0]=="selected") {
					valid=this.isSelected(e);
				}
					if (valid==false) {
						result=false;
					}
			}
			
/*
			if (navigator.appName=="Microsoft Internet Explorer") {
				e.onmouseover=new Function (this.tooltip_name+".show(this, event);");
				e.onmouseout=new Function (this.tooltip_name+".hide();");
			} else { //assume FireFox
				e.onmouseover=new Function ("event", this.tooltip_name+".show(this, event);");
				e.onmouseout=new Function ("event", this.tooltip_name+".hide();");
			}
*/			
		}

		return result;
	},
	//checking functions
	isValidEmailFormat: function(object) {
		//var email_format=/\S+@\S+\.\S+/;
		//var email_format=/^[a-z0-9]+[a-z0-9_\.\'\-]*@[a-z0-9]+[a-z0-9\.\-]*\.(([a-z]{2,6})|([0-9]{1,3}))$/;
		var email_format=/^[a-zA-Z0-9]+[a-zA-Z0-9_\.\'\-]*@[a-zA-Z0-9]+[a-zA-Z0-9\.\-]*\.(([a-zA-Z]{2,6})|([0-9]{1,3}))$/;
		return email_format.test(object.value);
	},
	isBlank: function(object) {
	  if (object.value.replace(/[\s]/g, "")=="") {
	     return true;
	  }
	  return false;
	},
	isMinimumCharacter: function(object, min) {
		if (this.trim(object.value).length>=min) {
			return true;
		}
		
		return false;
	},
	isSelected: function(object) {
	  if (object.options[object.selectedIndex].value=="") {
	     return false;
	  }
	  return true;
	},
	trim: function (stringToTrim) {
		return stringToTrim.replace(/^\s+|\s+$/g,"");
	},
	ltrim: function(stringToTrim) {
		return stringToTrim.replace(/^\s+/,"");
	},
	rtrim: function(stringToTrim) {
		return stringToTrim.replace(/\s+$/,"");
	}
}