function random_imglink(){
  var myimages=new Array()
  //specify random images below. You can have as many as you wish
	//myimages[1]="e-banner/CurrentTechnologiestoIncreasetheTransdermalDeliveryofDrugs.gif"
 	myimages[1]="e-banner/FrontiersinDrugDesign&DiscoveryVolume1.gif"
  	myimages[2]="e-banner/FrontiersinDrugDesign&DiscoveryVolume2.gif"
	myimages[3]="e-banner/FrontiersinDrugDesign&DiscoveryVolume3.gif"
  	myimages[4]="e-banner/FrontiersinDrugDesign&DiscoveryVolume4.gif"
    myimages[5]="e-banner/FrontiersinNaturalProductChemistry.gif"
	myimages[6]="e-banner/FrontiersinDrugDesign&DiscoveryVolume5.gif"
  //specify corresponding links below
  var imagelinks=new Array()
  //imagelinks[1]="http://benthamscience.com/ebooks/9781608051915/index.htm"
  imagelinks[1]="http://benthamscience.com/ebooks/9781608051991/index.htm"
  imagelinks[2]="http://benthamscience.com/ebooks/9781608052004/index.htm"
  imagelinks[3]="http://benthamscience.com/ebooks/9781608052011/index.htm"
  imagelinks[4]="http://benthamscience.com/ebooks/9781608052028/index.htm"
  imagelinks[5]="http://benthamscience.com/ebooks/9781608052127/index.htm"
    imagelinks[6]="http://benthamscience.com/ebooks/9781608052035/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()