Execute javascript in textarea of fckeditor

Dear all,
Can textarea of fckeditor execute javascript in it looks like after it's updated?

Example I create a tooltip:

<span ID="oToolTip0" STYLE="display:none;">
<span style="position: absolute; top:0; left:0; border:2px solid black; font:normal 10pt tahoma;
filter:progid:DXImageTransform.Microsoft.Gradient(GradientType=0,StartColorStr=orange, EndColorStr=#FFFFFF); padding:10px" >
Fckeditor
</span>
</span>

<span id="ttip0" onmouseover="var oPopup = window.createPopup();var lefter = event.offsetY;var topper = event.offsetX;oPopup.document.body.innerHTML =
oToolTip0.innerHTML;oPopup.show(topper, lefter, 154, 90, ttip0);">HI THERE!
</span>

In the textarea, it appears although I don't do mouseover.

Please help me.

Thanks in advance.