// JavaScript Document

/*
	Strip whitespace from the beginning and end of a string
	Input : a string
*/
function trim(str)
{
	return str.replace(/^\s+|\s+$/g,'');
}

/*
	Make sure that textBox only contain number
*/
function checkNumber(textBox)
{
	while(textBox.value.length > 0 && isNaN(textBox.value))
	{
	textBox.value = textBox.value.substring(0,textBox.value.length - 1);
	}
	
	textBox.value = trim(textBox.value);
}

/*
	Check if the form element is empty
	if it is display an alert box and focus to the element
*/
function isEmpty(formElement, message)
{
	
	formElement.value = trim(formElement.value);
	
	_isEmpty = false;
	if(formElement.value == '')
	{
		_isEmpty = true;
		alert(message);
		formElement.focus();
	}
	
	return _isEmpty;
	
}

function check(formElement, message)
{
	formElement.checked =  trim(formElement.checked);
	
	_check = false;
	
	if(formElement.checked == false)
	{
		_check = true;
		alert(message);
	}
	
	return _check;
}

function emailCheck(str) {
		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   alert("Invalid E-mail Address")
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   alert("Invalid E-mail Address")
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Invalid E-mail Address")
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Invalid E-mail Address")
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Invalid E-mail Address")
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Invalid E-mail Address")
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Invalid E-mail Address")
		    return false
		 }

 		 return true					
	}