function tblbg_chg(bgc) {
  bgdec = eval("0x"+bgc);
  rclr = Math.floor(bgdec / 0x10000);
  gclr = Math.floor((bgdec - rclr * 0x10000) / 0x100);
  bclr = bgdec - rclr * 0x10000 - gclr * 0x100;
  txt0="";
//  txt0+="現在選択されている背景色"+" : ";
  txt0+="16進数 = #"+bgc+" : ";
  txt0+="10進数 = "+bgdec+" : ";
  txt0+="R,G,B = "+rclr+", "+gclr+", "+bclr;
  document.getElementById("clratr").value = txt0;
  document.getElementById("clrtbl").style.backgroundColor = "#"+bgc;
}