JavaScript のデバッグ時にオブジェクトを調べるのに console.dir を使うと便利

<script type="text/javascript"><!--
function print_r(obj) {
var count_obj = 0;
    function _output(str) {
      　document.writeln(str + "<br/>");
    }
    function _print_r(obj, name, level) {
    	var s = "";
        if (obj == undefined || level > 4) return;
        for (var i = 0; i < level; i++) { s += " | "; }
        s += " - " + name + ":" + typeof(obj) + "=" + obj;
        _output(s);
        if (name == "document" || typeof(obj) != "object") return;
        for ( key in obj ) {
        if (count_obj++ > 150) return;
        	_print_r(obj[key], key, level + 1);
        }
    }
  	_print_r(obj, "*", 0);
}
//-->
</script>

console.dir(document)