function random_imglink(){
  var myimages=new Array()
  myimages[1]="e-banner/Molecular Mechanism and Morphology in Cancer copy.gif"
  myimages[2]="e-banner/Metal Based Functionally Graded Materials copy.gif"

  var imagelinks=new Array()
  imagelinks[1]="http://benthamscience.com/ebooks/9781608050734/index.htm"
  imagelinks[2]="http://benthamscience.com/ebooks/9781608050383/index.htm"

  var ry=Math.floor(Math.random()*myimages.length)

  if (ry==0)
     ry=1
     document.write('<a href='+'"'+imagelinks[ry]+'"'+' onclick="window.open(this.href); return false;"><img src="'+myimages[ry]+'" border=0></a>')
}

  random_imglink()