var zoomfactor = 0.05;

function zoomhelper()
  {
    if ( parseInt( whatcache.style.height ) > 10 )
    {
       whatcache.style.height = parseInt( whatcache.style.height ) + 
       parseInt( whatcache.style.height ) * zoomfactor * prefix
    }
  }

function zoom( originalH, what, state )
  {
       whatcache = eval( "document.images." + what )
       prefix = ( state == "in" )? 1 : -1

     if ( whatcache.style.width == "" ) 
  {  
     whatcache.style.height = originalH
  }
  else
  {
     zoomhelper()
  }
     beginzoom = setInterval( "zoomhelper()", 100 )
  }

function clearzoom()
  {
    if ( window.beginzoom )
      clearInterval( beginzoom )
  }