//find checked option for radio button
function getCheckedValue(radioObj) 
{
   if(!radioObj)
      return "";
   var radioLength = radioObj.length;
   if(radioLength == undefined)
   {
      if(radioObj.checked)
         return radioObj.value;
      else
	 return "";
   }
   for(var i = 0; i < radioLength; i++) 
   {
      if(radioObj[i].checked) 
      {
	return radioObj[i].value;
      }
   }
   return "";
}

//given <div> id, return obj style based on browser type
function getObjStyle(divId)
{
   var obj;
   
   if (document.getElementById)
       obj = document.getElementById(divId).style;//W3C DOM
   else if (document.layers) 
       obj = document.layers[divId]; //NS4
   else
       obj = document.all[divId].style; //IE5
   
   return obj;
}

//show or hide div. divId - <div> id, state: 0 - hide, 1 - show, 
//szX - width of the div, szY - height of the div
function displayDiv(divId, state, szX, szY)
{
   var obj = getObjStyle(divId);
   if (document.layers)
       obj.visibility = state ? "show" : "hide";  //NS4
   else
       obj.visibility = state ? "visible" : "hidden";  //W3C DOM
   
   if (state)
       displayCenterDiv(szX, szY, divId);
}


//display div at the center of the screen.  szX - width of the div, 
//szY - height of the div, divId - <div> id
function displayCenterDiv(szX, szY, divId) 
{ 
    var scrolledX, scrolledY, centerX, centerY; 
    var offsetX, offsetY, obj;

    //compute scrolled x and y
    if (self.pageYOffset) 
    { 
        scrolledX = self.pageXOffset; 
        scrolledY = self.pageYOffset; 
    } 
    else if (document.documentElement && document.documentElement.scrollTop) 
    { 
        scrolledX = document.documentElement.scrollLeft; 
        scrolledY = document.documentElement.scrollTop; 
    } 
    else if (document.body) 
    { 
        scrolledX = document.body.scrollLeft; 
        scrolledY = document.body.scrollTop; 
    } 

    //compute center x and y of browser's window 
    if (self.innerHeight) 
    { 
        centerX = self.innerWidth; 
        centerY = self.innerHeight; 
    } 
    else if (document.documentElement && document.documentElement.clientHeight) 
    { 
        centerX = document.documentElement.clientWidth; 
        centerY = document.documentElement.clientHeight; 
    } 
    else if (document.body) 
    { 
        centerX = document.body.clientWidth; 
        centerY = document.body.clientHeight; 
    } 
    
    //compute offset x and y
    offsetX = scrolledX + (centerX - szX)/ 2; 
    offsetY = scrolledY + (centerY - szY) / 2; 
    
    obj = getObjStyle(divId);
    obj.left = offsetX + 'px'; 
    obj.top = offsetY + 'px'; 
}