Mkto.validateField is generating a -3 spam score in my emails

Hi,

I just tried one of my emails to check the spam score and it's showing a -3 negative score. 

It identified a Javascript tag which could be dangerous, but I'm not sure why is there and if it can be removed.

• <script type="text/javascript"> Mkto.validateField = function(fld) { return true; } </script>

It looks like a validation for a form, but this is an email. Do you guys know what is it and if it can be removed?

I want to avoid being filtered into the junk/spam folder.