function changedesc(descName){
imgName = eval(descName + ".src")
   document.desc.src=imgName;
}
 function cleardesc(){
   document.desc.src=imgBlank.src;
}

/* preload images */
if(document.images){
imgBlank = new Image (600,90)
imgBlank.src = "images/home-desc-blank.jpg"

imgHome = new Image(600,90)
imgHome.src = "images/home-desc-home.jpg"

imgISA = new Image(600,90)
imgISA.src = "images/home-desc-isa.jpg"

imgIslam = new Image(600,90)
imgIslam.src = "images/home-desc-islam.jpg"

imgContact = new Image(600,90)
imgContact.src = "images/home-desc-contact.jpg" 
}