I have around 200ish domain name which I have done a 302 redirect at the domain registrar to a single domain. Just wondering if this is going to hurt the PR of the domain which all others are point to. Also should I have done the redirect in the header (index.html) or maybe javascript?
302s are temporary redirects. If those domain names are going to permanently point to a single domain, then you shiould use the 301 redirect - and only promote the main domain, not the 200+ redirected ones.
I don't think these 302 redirects will hurt your main domain. I would recommend to use 301 redirect so that you can pass the google trust of other domains to your main domain.