Modify Tag of WPC Layout Templates

Hi experts,

I've created a custom web page layout for WPC which is working fine so far. However, I have to execute some javascript "onload" of the page. Furthermore I want to remove the automatically added css classes (prtlBody urFontBaseFam urScrl) for this. Is there a way to access and modify the html body tag which is (I think) generated by the lyt:template tag?

thanks in advance for you help!

harald