problem with tab default value>?

I've put an example of what I'm talking about here

Notice when you click on the position...it doesn't always work. I think it's a problem setting the default start value.

var tabs_curtab = 'tabs0';
function goTabtabs (whichtab) {
getEl(tabs_curtab + 'td').className='bg1';
getEl(whichtab + 'td').className='bg2';
getEl(tabs_curtab).style.visibility='hidden';
getEl(whichtab).style.visibility='visible';
tabs_curtab = whichtab;

}

I want the default drop-down to be "tabs0", which is the Catchers.



Feel free to take a look at the source and let me know if you see anything...Any help would be appreciated!!