function checkFields()
{
	var _errors = "";
	// check email field
	if($("#input-email").length)
	{
		if($("#input-email").attr("value").length == 0)
		{
			_errors += "Email field is empty.\n";
		}
		else if (!$("#input-email").attr("value").match(new RegExp('^\\w+([-+.]\\w+)*@\\w+([-.]\\w+)*\\.\\w+([-.]\\w+)*$')))
		{
			_errors += "Incorrect Email address.\n";
		}
	}
	// check username input
	if($("#input-username").length)
	{
		if($("#input-username").attr("value").length == 0)
		{
			_errors += "Username field is empty.\n";
		}
	}
	// check message text input
	if($("#textarea-message").length)
	{
		if($("#textarea-message").attr("value").length == 0)
		{
			_errors += "Message field is empty.\n";
		}
	}
	// errors results
	if(_errors.length > 0)
	{
		if($("#warning-label").length) {
			$("#warning-label").text(_errors);
			$("#warning-label").css('display', 'block');
		}
		else {
			alert(_errors);
		}		
		return false;
	}
	else
	{
		$("#warning-label").css('display', 'none');
		return true;
	}
}

// clear input fields
function resetForm() {
	$("#input-email").val("");
	$("#input-username").val("");
	$("#textarea-message").val("");

	$("#warning-label").css("display", "none");
	$("#popup-form").css("display", "block");
	$("#message-posted .thank-you").css("top", "-9999px");
}

// check form values
function checkForm() {
	var _submit = document.getElementById('popup-submit');
	if(_submit) {
		_submit.onclick = function () {
			if(!checkFields()) {
				return false;
			}
		}
	}
}

if (window.addEventListener) window.addEventListener("load", checkForm, false);
else if (window.attachEvent) window.attachEvent("onload", checkForm);