/* image swapping code */

var imagearray=new Array();
/* imagedata object should be added to this array. see PhotoAlbum as an example */

function imagedata(url,title,height,width)
{this.url=url;					// url of image
 this.title=title;				// image title (alt text)
 this.height=height;			// image height
 this.width=width;				// image width
};

var currentimage=0;				// current displayed image
var imageresize=false;			// if the main image will resize (PhotoAlbum sets in ASPX code)


// display image n (0-based) using image control ctl and optional label (title)
function DisplayImage(n)
{var ctl=document.getElementById('DefaultPhotoImage');
 var labelctl=document.getElementById('labelMainPhoto');
 if (ctl!=null)
 
     		
   // is image within imagedata range
   if (n>=0 && n<imagearray.length)
     {ctl.src=imagearray[n].url;
      ctl.title=imagearray[n].title;
      // optionally resize
      if (imageresize)
        {ctl.width=imagearray[n].width;
	     ctl.height=imagearray[n].height;
        }
      // optional label control  
      if (labelctl!=null)
        labelctl.innerHTML=imagearray[n].title;
	  currentimage=n;    
     };
 UpdateNavigation();
};

function UpdateNavigation()
{var pctl=document.getElementById('prev');
 var nctl=document.getElementById('next');
 if (pctl!=null) pctl.style.visibility=(imagearray.length>0)?'visible':'hidden';				
 if (nctl!=null) nctl.style.visibility=(imagearray.length>0)?'visible':'hidden';
}

function displayNextImage()
{
  if (currentimage==0)
    currentimage = imagearray.length;
	
  DisplayImage(--currentimage);
}

function displayPreviousImage()
{
  if (currentimage==imagearray.length-1)
    currentimage = -1;

   DisplayImage(++currentimage);
}