norm1 = new Image();
norm1.src = "images/bband.gif";

norm2 = new Image();
norm2.src = "images/coloc.gif";

norm3 = new Image();
norm3.src = "images/t1.gif";

norm4 = new Image();
norm4.src = "images/sec.gif";

norm5 = new Image();
norm5.src = "images/dsl.gif";

norm6 = new Image();
norm6.src = "images/web.gif";

norm7 = new Image();
norm7.src = "images/cont.gif";

norm8 = new Image();
norm8.src = "images/tsup.gif";


 over1= new Image();
 over1.src = "images/bband_ov.gif";
over2= new Image();
 over2.src = "images/coloc_ov.gif";
over3= new Image();
 over3.src = "images/t1_ov.gif";
over4= new Image();
 over4.src = "images/sec_ov.gif";
over5= new Image();
 over5.src = "images/dsl_ov.gif";
over6= new Image();
 over6.src = "images/web_ov.gif";
over7= new Image();
 over7.src = "images/cont_ov.gif";
over8= new Image();
 over8.src = "images/tsup_ov.gif";


function rollOn(num) {
   if(document.images) {
      eval('document.norm'+num+'.src='+'over'+num+'.src');
   }
}

function rollOff(num) {
   if(document.images) {
      eval('document.norm'+num+'.src='+'norm'+num+'.src');
   }
}