head.html

<script>
{
  let timer = 0;

  function showmesg(t, form) {

     if (timer == 0) {
       timer = new Date();
     }

     let tm = new Date();

     if (tm - timer > 300) {
       t = '------------------------------\n' + t;
     }

     let area = document.forms[form + 'form'].getElementsByTagName('textarea')[0];

     area.value += t + '\n';
     area.scrollTop = area.scrollHeight;

     timer = tm;
  }

  function logMouse(e) {
     let evt = e.type;
     while (evt.length < 11) evt += ' ';
     showmesg(evt + " button=" + e.button, 'test')
     return false;
  }

  function keyval(n) {
     if (n == null) return 'undefined';
     let s = '' + n;
     if (n >= 32 && n < 127) s += ' ' + String.fromCharCode(n);
     while (s.length < 6) s += ' ';
     return s;
  }


  function logClear(form) {
  	timer = 0;
  	document.forms[form+'form'].getElementsByTagName('textarea')[0].value ='';
  	lines = 0;
  }

  window.logClear = logClear;
  window.logMouse = logMouse;
}
</script>