function random_imglink(){
  var myimages=new Array()
  //specify random images below. You can have as many as you wish
  //myimages[1]="e-banner/Mitigate-Magnetic.gif"
  //myimages[2]="e-banner/Riesz-Spaces.gif"
  //myimages[3]="e-banner/Amelogenins_Multi.gif"
    myimages[1]="e-banner/Amelogenins Multifaceted.gif"
  //specify corresponding links below
  var imagelinks=new Array()
  //imagelinks[1]="http://benthamscience.com/ebooks/9781608050390/index.htm"
  //imagelinks[2]="http://benthamscience.com/ebooks/9781608050031/index.htm"
  //imagelinks[3]="http://benthamscience.com/ebooks/9781608051717/index.htm"
  imagelinks[1]="http://benthamscience.com/ebooks/9781608051717/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()