function display_error_message(err) 
{
	obj = document.getElementById("formError");
	obj.style.display = "block";
	
	mg = "<h3>The form could not be submitted because of the following reasons:</h3><ul>";
	
	for (var i=0; i<err.length; i++) {
		mg += "<li>"+err[i]+"</li>";
	}
	
	mg += "</ul>";
	
	obj.innerHTML = mg;
	
}

function hide_error_message() {
		obj = document.getElementById("formError");
		obj.style.display = "none";
		obj.innerHTML = '';
}


// if (!validData(field_name)) 
function validData(formID)
{ 
	with (formID) {
		if (value==null || value=="") {return false;}
		else {return true;}
	}
}


// if (!validEmail(field_name)) 
function validEmail(formID) 
{
	with (formID) {
		var emailRegExp = /^[_a-zA-Z0-9-]+(\.[_a-zA-Z0-9-]+)*@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)*\.(([0-9]{ 1,3})|([a-zA-Z]{2,3})|(aero|coop|info|museum|name))$/;
		if (emailRegExp.test(value)) {
			return true; 
		} else {
			return false;
		}
	}
} 


// if (!validNumber(field_name)) 
function validNumber(formID) 
{	
		inputStr = formID.value.toString()
		for (var i = 0; i < inputStr.length; i++)
			{ 
			var oneChar = inputStr.charAt(i);if ((oneChar < "0" || oneChar > "9")) { if (oneChar !=" ") {return false;}}
			};
		return true;
}


// if (!validLength(field_name, length)) 
function validLength(formID, len) 
{	
		inputStr = formID.value.toString()
		if (inputStr.length < len) {
			return false;
		}
		return true;
}


// if (!validMatch(field_name_1, field_name_2)) 
function validMatch(formID, formID2) 
{	
		inputStr 	= formID.value.toString()
		inputStr2 = formID2.value.toString()
		if (inputStr != inputStr2) {
			return false;
		}
		return true;
}


// if (!validDropDown(dropdown_name, string_to_search_for)) 
function validDropDown(formID, valueString) 
{
	with (formID) {
		if (formID.value==valueString) {return false;}
		else {return true;}
	}
}


// if (!validRadio(radio_name, no_of_buttons)) 
function validRadio(formID, number) 
{
	with (formID) {
		for (var i=0; i<number; i++){
			if (formID[i].checked==true) {return true;}
		}
		return false;
	}
}


// if (!validCheckbox(checkbox_name)) 
function validCheckbox(formID) 
{
	with (formID) {
		if (formID.checked==false) {
			return false;
		}
		return true;
	}
}


// checkbox_array = new Array(cb01, cb02, cb03, cb04) 
// if (!validCheckboxes(checkbox_array)) 
function validCheckboxes(formArray) 
{
	for (var i=0; i<formArray.length; i++) {
		if (formArray[i].checked==true) {return true;}
	}
	return false;
}


// if (!validAlphanumeric(field_name)) 
function validAlphanumeric(formID)
{ 
	with (formID) {
		for (var i=0; i<value.length; i++) {
			var c = value.charAt(i);
			if (! (isLetter(c) || isDigit(c) ) ) {
				return false;
			}
		}
		return true;
	}
}

function isLetter (c)
{   return ( ((c >= "a") && (c <= "z")) || ((c >= "A") && (c <= "Z")) )
}

function isDigit (c)
{   return ((c >= "0") && (c <= "9"))
}