それにしてもｖ氏は、優しいねぇ〜。

JavaScript

おかげさまで、一応完成です。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<title>test</title>

<p id="pp">
<input type="text" id="y" size="6">
<input type="text" id="m" size="4">
<input type="text" id="d" size="4">
</p>
<p id="qq">
<input type="text" id="yy" size="6">
<input type="text" id="mm" size="4">
<input type="text" id="dd" size="4">
</p>

<script type="text/javascript">
//@cc_on

var AutoFocus = (function (createListener) {
  return function (target, css_on, css_out) {
    var listener = createListener(css_on, css_out);
  
  target./*@if (@_jscript) attachEvent('on' + @else@*/ addEventListener(/*@end@*/
    /*@if (@_jscript) 'focusin' @else@*/ 'focus' /*@end@*/, listener, true);
    
  target./*@if (@_jscript) attachEvent('on' + @else@*/ addEventListener(/*@end@*/
    /*@if (@_jscript) 'focusout' @else@*/ 'blur' /*@end@*/, listener, true);
  };
})(
  function (css_on, css_out) {
    return function (evt) {
      var e  = evt./*@if (@_jscript) srcElement @else@*/ target /*@end@*/;
      if ( /INPUT|TEXTAREA/.test(e.nodeName) && ! /checkbox|radio/.test(e.type) ) {
        e.style.cssText = /*@if (@_jscript) 'focusin' @else@*/ 'focus' /*@end@*/ === evt.type ? css_on: css_out;
      }
    };
  });


AutoFocus(document.getElementById('pp'), 'background-color:#fee','');

AutoFocus(document.getElementById('qq'), 'background-color:#eef','');

</script>