var mainPic = null;      // ahh... the main picture
var mainCaption = null;  // the main caption!
var activeBtn = null;

function getMainPic()
{
  // If DOM1 supported ...
  if (document.getElementById){

		mainPic = document.getElementById('mainPic');
//		mainPic.onload = 'makeVis(mainPic)';
		mainCaption = document.getElementById('mainCaption');

  }
}

function btnOver(btnImg)
{
	var imgName = null;

	if (mainPic==null) {
		getMainPic();
	}

  if (mainPic!=null && btnImg!=null && btnImg!=activeBtn){

		if (activeBtn!=null) {

			btnOff(activeBtn);

		}

		imgName = btnImg.id.replace(/[^0-9]/g, '');
		btnImg.src = btnImg.src.replace(/([0-9]+)btnf.jpg/, '$1btn.jpg');
		mainPic.style.visibility = "hidden";
		mainPic.width = workwidth[imgName];
		mainPic.src = btnImg.src.replace(/([0-9]+)[a-z]+.jpg/, '$1.jpg');

		activeBtn = btnImg;
//		mainCaption.innerHTML = worklabel[imgName];
		mainCaption.firstChild.nodeValue = worklabel[imgName];

	}
}

function btnOff(btnImg)
{
  if(mainPic!=null && btnImg!=null){

		btnImg.src = btnImg.src.replace(/([0-9]+)btn.jpg/, '$1btnf.jpg');
		
	}
}

function makeVis(theImg)
{
		theImg.style.visibility = "visible";
}