function show(submenu)
{

var menu = document.getElementById(submenu);

if (menu.style.display != "block")
	menu.style.display = "block";
else
	menu.style.display = "none";
	
}

function swap(img_name, img_src)
{
   document[img_name].src = img_src;
}

function checkform()
{
	var name_lgt = document.feedback.name.value.length;
	var email_lgt = document.feedback.email.value.length;
	
	if(name_lgt==0)
	{
		window.alert("Please kindly fill in your name!");
		return false
	}

	if(email_lgt == 0 )
	{
		window.alert("Please kindly fill in your email, so we could contact you!");
		return false;
	}
	else
	{
		if(document.feedback.email.value.indexOf("@")==-1 || document.feedback.email.value.indexOf("@")==0 || document.feedback.email.value.indexOf("@")+1== document.feedback.email.value.length)
		{
			window.alert("Invalid email. Please kindly fill in a valid email!");
			return false;

		}
	}

}

function checkcustomerform()
{
	var name_lgt = document.feedback.name.value.length;
	var email_lgt = document.feedback.email.value.length;
	var tel_lgt = document.feedback.tel.value.length;
	
	if(name_lgt==0)
	{
		window.alert("Please kindly fill in your name!");
		return false
	}

	if(email_lgt == 0 )
	{
		window.alert("Please kindly fill in your email, so we could contact you!");
		return false;
	}
	else
	{
		if(document.feedback.email.value.indexOf("@")==-1 || document.feedback.email.value.indexOf("@")==0 || document.feedback.email.value.indexOf("@")+1== document.feedback.email.value.length)
		{
			window.alert("Invalid email. Please kindly fill in a valid email!");
			return false;

		}
	}
	
	if(tel_lgt==0)
	{
		window.alert("Please kindly fill in your contact number, so we could contact you!");
		return false
	}

}

function pop(url,windowname,w,h,x,y)
{
window.open(url,windowname,"resizable=no,toolbar=no,scrollbars=no,menubar=no,status=no,directories=no,width="+w+",height="+h+",left="+x+",top="+y+"");
}