Changing Colors of Values in Pivot Table

[kpcollier]

Trying to do something similar to this post 

However, its a bit different. I have a Trainings Table with records of all Trainings/Certificates our employees need. These records are being used as fields at the top of my pivot table. On the left side are Employee Names coming from an Employee Table. Thirdly, there is a CertificateTable that pulls them together. This table consists of the employee name, trainer, training, issue and expiration dates. 

The Values for this Pivot Table are the Expiration Dates in short date form, which is a field in the CertificateTable. Is there a way I can make the cell alone (not the entire column or row) turn red if that date is within 30 days of expiring?

I can't insert an HTML Block on the Pivot Table Wizard, however it allows me to insert a header and footer.

Thanks.

[kpcollier]

The IDs for Pivot Tables seem to have random(), so it is different every single time the page is loaded. It makes it impossible to catch the element with getElementByID(). I've tried ClassName and received an error, I'm using up to date Chrome so idk why. Any help is appreciated.

[kpcollier]

I can get it to work on the Drill Down Report (results) page with this script..

<script>
var isi = document.getElementById("visi[@field:Certificate_Table_Certificate_Number]");
 var now = new Date();
var expiration = new Date("[@field:Certificate_Table_Expiration_Date*]"); 
if(expiration < now){
isi.innerHTML = '[@field:Certificate_Table_Expiration_Date*]';
isi.style.backgroundColor='red';
}
else{
isi.innerHTML = '[@field:Certificate_Table_Expiration_Date*]';
}
</script>

Works great in every way besides being on the right page.  Tried splitting it up with the div in the header and the script in the footer and it doesn't work.