fill checkbox when text is in text area in javascript
<p>I have a text area form like this one: </p>

<pre><code>&lt;input id="sg_0" name="sjalfgefid" type="text" class="letur hvitur" size="8" maxlength="40" value=""&gt;&lt;/td&gt;
</code></pre>

<p>and a Checkbox next to it:</p>

<pre><code>&lt;input type="Checkbox" id="cb0" name="innsent" tegund="val" gildi="eink" value="0" number="0" parents="1" onclick="hakaVid(this)"&gt;
</code></pre>

<p>I want the checkbox to be filled when some text is written in the text area. And when the user deletes all the text from the textbox, I want the checkbox to update immediately
How can I possibly do this ?</p>
