url0 = document.URL;
  idx0 = url0.indexOf("/htm",0);
  if (idx0 == -1) idx0 = url0.indexOf("\\htm",0);
  if (idx0 == -1) idx0 = url0.indexOf("/tool",0);
  if (idx0 == -1) idx0 = url0.indexOf("\\tool",0);
  document.write("<a href='/tool_srcview.html?");
  document.write(url0.substring(idx0));
  document.write("'>このテキストの表示</a><br>");