var BookArray = new Array ( // dense array
  "013084408X"
, "0133957241"
, "0966498054"
, "0314066756"
, "0072355964"
, "0134638948"
, "0471241865"
, "1402071418"
, "1401840302"
, "0130995274"
, "1402077106"
, "013140539X"
, "0130621218"
, "0072838787"
, "0792376447"
, "047198325X"
, "0792393082"
, "0534551610"
, "0471429767"
, "0070163332"
, "0792399218"
, "0818677163"
, "0792393643"
, "0471150428"
, "013141884X"
, "0130669466"
, "1580531318"
, "0130289043"
, "0974364967"
, "0070087342"
, "0131433474"
, "1402074018"
, "0131413090"
, "0849378389"
, "0750676175"
, "0750677309"
, "0792397460"
, "1402080255"
, "0792373685"
, "3540654453"
, "0792384776"
, "1402071132"
, "1402075308"
, "0387260498"
// new books start here
, "0387366415"
, "0123742102"
, "0387262326"
, "1402080271"
// SystemVerilog
, "0387765298"
, "0387333991"
, "0387292217"
, "0981656218"
, "0387717382"
, "0387255389"
, "0387260498"
, "0971199418"
, "0071489045"
, "0387717145"
, "0970539479"
, "0387255435"
, "0970539495"
);

// Choose randomly if the variable 'asin' is not defined for 'Book of the Month'

var scripts = document.getElementsByTagName('script');
var myScript = scripts[ scripts.length - 1 ];
var queryString = myScript.src.replace(/^[^\?]+\??/,'');
var params = parseQuery( queryString );
//alert (params['asin']);

var RandomBookIndex = Math.floor(Math.random()*BookArray.length);
var botmIndex = findBotmIndex(BookArray.length);

document.write('<iframe src="http://rcm.amazon.com/e/cm?t=projectveripa-20&o=1&p=8&l=as1&asins=');
if (params['asin'] == undefined) { 
   if (params['method'] == 'botm') { 
      document.write(BookArray[botmIndex]);
   } else {
      document.write(BookArray[RandomBookIndex]);
   }
}
else {
   document.write(params['asin']);
}
document.write('&fc1=000000&=1&lc1=0000ff&bc1=000000&lt1=_blank&IS2=1&f=ifr&bg1=ffffff&f=ifr" width="125" height="240" scrolling="no" marginwidth="0" marginheight="0" frameborder="0"></iframe>');

// from http://feather.elektrum.org/book/src.html

function parseQuery ( query ) {
   var Params = new Object ();
   if ( ! query ) return Params; // return empty object
   var Pairs = query.split(/[;&]/);
   for ( var i = 0; i < Pairs.length; i++ ) {
      var KeyVal = Pairs[i].split('=');
      if ( ! KeyVal || KeyVal.length != 2 ) continue;
      var key = unescape( KeyVal[0] );
      var val = unescape( KeyVal[1] );
      val = val.replace(/\+/g, ' ');
      Params[key] = val;
   }
   return Params;
}

function findBotmIndex (BookArray_length){ 
	var d = new Date();
	var curr_month = d.getMonth()+1;
	var curr_year = d.getFullYear();
	return (curr_year*100+curr_month)%BookArray_length;
}