var currentPanel = 1;
function showPanel(panelNum, trgtURL){
  //hide visible panel, show selected panel, set tab
  hidePanel();
//  document.getElementById('panel'+panelNum).style.visibility = 'visible';
  window.open (trgtURL, "mainFrame");
  currentPanel = panelNum;
  setState(panelNum);
}
function openNewWindow(panelNum, trgtURL){
  window.open (trgtURL, "_blank");
}
function hidePanel(){
  //hide visible panel, unhilite tab (back to its normal color)
//  document.getElementById('panel'+currentPanel).style.visibility = 'hidden';
  document.getElementById('tab'+currentPanel).style.backgroundColor = 'Green';
  document.getElementById('tab'+currentPanel).style.color = 'white';
}
function setState(tabNum){
  if(tabNum==currentPanel){
        // Selected tab so highlight it.
   // document.getElementById('tab'+tabNum).style.backgroundColor = '#ddddff';
    document.getElementById('tab'+tabNum).style.backgroundColor = '#00CC00';
    document.getElementById('tab'+tabNum).style.color = 'yellow';
  }else{
        // Back to it's normal color
    document.getElementById('tab'+tabNum).style.backgroundColor = 'Green';
    document.getElementById('tab'+tabNum).style.color = 'white';
  }
}
function hover(tab){
//  tab.style.backgroundColor = 'ddddff';
    // Hover over it should change appearance
  tab.style.backgroundColor = 'yellow'; 
  tab.style.color = 'Green'; 
}