Cross domain iframe

Avg Bid (USD)
Project Budget (USD)
$30 - $250

Project Description:
Here is my problem I am a programmer but I have a problem I am trying to solve.
I have domain A hosted by me I have an iframe on Domain A that calls a site from Domain B not hosted by me.
I would like to be able to auto fill out the sign up form on Site B with variables from site A and submit it name and email.
It is not so simple as most browsers do not allow javascript to access the DOM elements of another site.

If anyone can help please let me know.

Skills required:
Perl, PHP, Software Architecture
About the employer:
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