Make WP STOP adding to my CODE!!!!

Running Atpualpa on 3.1.2 (can I also add that everytime I download a new version, there’s another new version within a week? HATE THAT!)

I use wordpress to create RSS feeds for my ever changing product line. I use Mals-e for my cart.

My a script I need for an item with lots of color choices in my Cart code should be this:

<script type=”text/javascript”>
function tally(that){
result=0;
for(i=0;i<that.form.elements.length;i++)
{
if (that.form.elements[i].name.indexOf(“product[]”)>-1){result += that.form.elements[i].value-0;}
}that.form.qty.value = result;
}
</script>

But WP adds a </that> on the last line!

<script type=”text/javascript”>
function tally(that){
result=0;
for(i=0;i<that .form.elements.length;i++) { if (that.form.elements[i].name.indexOf(“product[]”)><p>-1){result += that.form.elements[i].value-0;}
}that.form.qty.value = result;
}
</p></that></script> </p>

Considering there is no <that> in the beginning… why add this code?? And how do I work around it???