// to show and hide thumbnails.

function HideContent(d) 
{
	if (d.length < 1) { return; }
	document.getElementById(d).style.display = "none";
}

function ShowContent(d) 
{
	if (d.length < 1) { return; }
	document.getElementById(d).style.display = "";
}

function ReverseContentDisplay(d) 
{
	if (d.length < 1) { return; }
	if (document.getElementById(d).style.display == "none") 
		{ document.getElementById(d).style.display = ""; }
	else { document.getElementById(d).style.display = "none"; }
}


/********************** GET MOUSE XY ********************/

// Detect if the browser is IE or not.
// If it is not IE, we assume that the browser is NS.
var IE = document.all?true:false

// If NS -- that is, !IE -- then set up for mouse capture
if (!IE) document.captureEvents(Event.MOUSEMOVE)

// Set-up to use getMouseXY function onMouseMove
document.onmousemove = getMouseXY;

// Temporary variables to hold mouse x-y pos.s
var tempX = 0
var tempY = 0

// Main function to retrieve mouse x-y pos.s

function getMouseXY(e) 
{
  if (IE) { // grab the x-y pos.s if browser is IE
    tempX = event.clientX + document.body.scrollLeft
    tempY = event.clientY + document.body.scrollTop
  } else {  // grab the x-y pos.s if browser is NS
    tempX = e.pageX
    tempY = e.pageY
  }  
  // catch possible negative values in NS4
  if (tempX < 0){tempX = 0}
  if (tempY < 0){tempY = 0}
}

/********************** END OF GET MOUSE XY ********************/

function showAbout()
{
	ReverseContentDisplay('about'); 
	HideContent('contact'); 
}
function showContact()
{
	HideContent('about'); 
	ReverseContentDisplay('contact'); 
}

function isEmpty(name, email, subject, message)
{
	//change "field1, field2 and field3" to your field names
	strfield1 = document.forms[0].name.value;
	strfield3 = document.forms[0].subject.value;
	strfield4 = document.forms[0].message.value;

	//name field
	if (strfield1 == "" || strfield1 == null || !isNaN(strfield1) || strfield1.charAt(0) == ' ')
	{
		alert("Please enter your name.");
		return false;
	}

	//subject field 
	if (strfield3 == "" || strfield3 == null || strfield3.charAt(0) == ' ')
	{
		alert("Please enter a subject.")
		return false;
	}

	//message field 
	if (strfield4 == "" || strfield4 == null || strfield4.charAt(0) == ' ')
	{
		alert("Please enter a message.")
		return false;
	}
	return true;
}

//function to check valid email address
function isValidEmail(strEmail)
{
  validRegExp = /^[^@]+@[^@]+.[a-z]{2,}$/i;

  strEmail = document.forms[0].email.value;

  // search email text for regular exp matches
  if (strEmail.search(validRegExp) == -1) 
  {
		alert("Please enter a valid email.");
		return false;
	} 
	return true; 
}

function checkForm(form)
{
	if (isEmpty(form.field1))
	{
  	if (isEmpty(form.field3))
  	{
    	if (isEmpty(form.field4))
    	{
				if (isValidEmail(form.email))
				{
		  		return true;
				}
	  	}
  	}
	}
	return false;
}