function random_imglink(){
  var myimages=new Array()
  //specify random images below. You can have as many as you wish
 myimages[1]="e-banner/Frontiers_in_Drug_Design5.gif"
 myimages[2]="e-banner/Causal_Inference.gif"
 myimages[3]="e-banner/Fro_Anti-infective_DD.gif"
 myimages[4]="e-banner/Frontiers_in_Drug_Design.gif"
 myimages[5]="e-banner/Frontiers_in_Drug_Design2.gif"
 myimages[6]="e-banner/Frontiers_in_Drug_Design3.gif"
 myimages[7]="e-banner/Frontiers_in_Drug_Design4.gif"
 myimages[8]="e-banner/Protozoa.gif" 

  //specify corresponding links below
  var imagelinks=new Array()

imagelinks[1]="http://benthamscience.com/ebooks/9781608052035/index.htm"
imagelinks[2]="http://benthamscience.com/ebooks/9781608051816/index.htm"
imagelinks[3]="http://benthamscience.com/ebooks/9781608051588/index.htm"
imagelinks[4]="http://benthamscience.com/ebooks/9781608051991/index.htm"
imagelinks[5]="http://benthamscience.com/ebooks/9781608052004/index.htm"
imagelinks[6]="http://benthamscience.com/ebooks/9781608052011/index.htm"
imagelinks[7]="http://benthamscience.com/ebooks/9781608052028/index.htm"
imagelinks[8]="http://benthamscience.com/ebooks/9781608051489/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()