if(document.images) {
 var imgs = new Array();
 imgs[0] = new Image();  imgs[0].src = "image/o_concept.png";
 imgs[1] = new Image();  imgs[1].src = "image/concept.png";
 imgs[2] = new Image();  imgs[2].src = "image/o_protein.png";
 imgs[3] = new Image();  imgs[3].src = "image/protein.png";
 imgs[4] = new Image();  imgs[4].src = "image/o_cell.png";
 imgs[5] = new Image();  imgs[5].src = "image/cell.png";
 imgs[6] = new Image();  imgs[6].src = "image/o_RNA.png";
 imgs[7] = new Image();  imgs[7].src = "image/RNA.png";
 imgs[8] = new Image();  imgs[8].src = "image/o_integra.png";
 imgs[9] = new Image();  imgs[9].src = "image/integra.png";
 imgs[10] = new Image();  imgs[10].src = "image/o_info.png";
 imgs[11] = new Image();  imgs[11].src = "image/info.png";
 imgs[12] = new Image();  imgs[12].src = "image/o_japanese.png";
 imgs[13] = new Image();  imgs[13].src = "image/japanese.png";


}

function chgimg(id, imgname) {
 if(document.images) {
  if(imgs[imgname]) {
    document.images[id].src = imgs[imgname].src;
  }
  else {
    document.images[id].src = imgname;
  }
 }
}



function MenuOn(x){
obj=document.getElementById
("submenu"+x).style.visibility="visible";
}
function MenuOff(x){
obj=document.getElementById
("submenu"+x).style.visibility="hidden";
}