HTML Form > CRM debug

Hi I' have a form (generated by a CRM, We have to hide some fields, and a js does some filed velues work, very simple). the standard generated HTML is ok but our integration used to work but leads to blank page now...
We need someone that can analyse the current code and make it work.
We cannot redo the whole integration and js, will need to read and analyse the script.
Sharp eye / console would fix it in minutes (but we are not qualified :) )

thanks