Question : disable local back button when specific page loads in iframe

I have a back button on my main site.  I have a blog (with blogger) that loads into an iframe.  I also have a cname from my site pointing there, so blog.mysite.com.  I'm assuming the browsers are referencing it as a different site.  So that's what I'm trying to do, disable the back button once my blog is up, but have it enabled any other time.  I've tried multiple things that I think should work, but none have so far.  I figured I could pass a function from the blog site up to the parent, but nothing so far.  Thanks in advance

Answer : disable local back button when specific page loads in iframe

It's a scripted back button, not the browser back, so what I ended up doing was made another page1 (on my domain) put the script in to dissable the back button on my page and nested blog.mysite.com on that page1. Then on the main page the src is now page1 instead of blog.mysite.com and that took care of it.