Highlight Filter

Hi all,

I'm sure this is dead easy for anyone who knows Javascript but I don't know anything about it!

I've produced a report but would like 2 highlights.  One highlight shows average % profit where the pre-sales field is blank and the 2nd highlight shows the average % profit where the pre-sales field is not blank.

So, for me, I think all i need to know is the small bit of script that goes into the filter part of the highlight that tells it to check the pre-sales field is blank or not.

Thanks for your help