size of data in a form element

[PatrickLewis]

Is there any way to the size in Kb of the value of a specific form element? Say, 10 lines of text in a textarea is 1.5k?

[Vladdy]

<textarea name="myText" onkeyup="updateSize(this)"></textarea>
<p>Size of text: <span id="textSize">0</span> kB</p>

<script type="text/javascript">
function updateSize(ta)
{ document.getElementById('textSize').firstChild.nodeValue = 0.001*ta.value.length;
}
</script>