// 08/09/08 c.Goodform Design
var Thisbutton=0;                              // this button number
var Griddiv = document.getElementById('Grid'); // thumbs grid object
var Maindiv = document.getElementById('Main'); // main div object
var Mainimg = document.getElementById('MainImage'); // main image object
var Descmsg = document.getElementById('Descrip');   // desc message object

// mainline stuff; set thumbnail objects' onclick function
for (i=1;i <= 20; i++)
{ if( ! (obj = document.getElementById('thb'+i) ) ) break;
  obj.onclick = function(){ShowMain(this)};
}
var Imax = --i;
//set next / previous arrows onclick function, save original images
var NextArrow='next', PrevArrow='previous';
var NextArw = document.getElementById(NextArrow);  // next obj
var PrevArw = document.getElementById(PrevArrow);  // prev obj
PrevArw.onclick=function(){ArrowImg(this)};
NextArw.onclick=function(){ArrowImg(this)};
var PrevImg = PrevArw.src;
var NextImg = NextArw.src;

document.getElementById('close').onclick=function(){ShowGrid()};

// functions
function ShowMain(obj)
{ var id = obj.id;          // this is thbn n=1,2,..
  var len= id.length, c
  Thisbutton = '';
  for( ; len>0; len--)     // strips off the number from right side of id
   if( !(isNaN(c=id.substring(len-1,len))) ) Thisbutton = c+''+Thisbutton;

  Descmsg.innerHTML= Desc[Thisbutton];

// convert xxxxthb.jpg -> xxxx.jpg
  Mainimg.src = obj.src.substring(0,obj.src.length-7)+'.jpg';

  Maindiv.style.visibility = 'visible';
  Griddiv.style.visibility = 'hidden';  
// make invisible next/prev buttons if at beginning/at end
 if( Thisbutton == 1 )
     PrevArw.src='Images/null.gif'; else PrevArw.src=PrevImg;
 if( Thisbutton == Imax )
     NextArw.src='Images/null.gif'; else NextArw.src=NextImg;
}
function ShowGrid()
{ 
  Griddiv.style.visibility = 'visible';
  Maindiv.style.visibility = 'hidden';
  Mainimg.src='null.gif';
  Descmsg.innerHTML='';
}
function ArrowImg(obj)
{ var arrowid = obj.id;
  var button = Thisbutton;
  if( arrowid==PrevArrow ) button--; else button++;
  if( button < 1 || button > Imax ) return false;
  ShowMain(document.getElementById('thb'+button));
}
// end