PRE Tag with Line Numbers

https://plus.google.com/108949996304093815163/about

by J. Albert Bowden

HTML

<pre><code>&lt;div class="example"&gt;
    &lt;span&gt;Lorem ipsum dolor sit amet...&lt;/span&gt;
&lt;/div&gt;</code></pre>
<pre><code>(function() {
    var s = document.createElement('script');
        s.id = "some-id";
        s.type = "text/javascript";
    document.body.appendChild(s);
})();</code></pre>

CSS

body {background-color:white;padding:50px 50px}

pre {
  background-color:#eee;
  overflow:auto;
  margin:0 0 1em;
  padding:.5em 1em;
}

pre code,
pre .line-number {
  /* Ukuran line-height antara teks di dalam tag <code> dan <span class="line-number"> harus sama! */
  font:normal normal 12px/14px "Courier New",Courier,Monospace;
  color:black;
  display:block;
}

pre .line-number {
  float:left;
  margin:0 1em 0 -1em;
  border-right:1px solid;
  text-align:right;
}

pre .line-number span {
  display:block;
  padding:0 .5em 0 1em;
}

pre .cl {
  display:block;
  clear:both;
}

JavaScript

(function() {
    var pre = document.getElementsByTagName('pre'),
        pl = pre.length;
    for (var i = 0; i < pl; i++) {
        pre[i].innerHTML = '<span class="line-number"></span>' + pre[i].innerHTML + '<span class="cl"></span>';
        var num = pre[i].innerHTML.split(/\n/).length;
        for (var j = 0; j < num; j++) {
            var line_num = pre[i].getElementsByTagName('span')[0];
            line_num.innerHTML += '<span>' + (j + 1) + '</span>';
        }
    }
})();