function gene_window(mypage, myname, w, h, scroll) {
  var win_width = (screen.width - w) / 2;
  var win_height = (screen.height - h) / 2;
  win_detail = 'height='+h+',width='+w+',top='+win_height+',left='+win_width+',scrollbars='+scroll;
  win = window.open(mypage, myname, win_detail)
  if (parseInt(navigator.appVersion) >= 4) { win.window.focus(); }
}

function subwin1(){
window.open('how-to.htm','miniwin',
'resizable=no,menubar=no,status=no,location=no,scrollbars=yes,toolbar=yes,width=460,height=500,left=50px,top=50px');}

function subwin2(){
window.open('how-to.htm#aaa','miniwin',
'resizable=no,menubar=no,status=no,location=no,scrollbars=yes,toolbar=yes,width=460,height=500,left=50px,top=50px');}