In the example below, when I click the button, it says \"Load was performed\" but no text is shown.
I have a clientaccesspolicy.xml
Clientaccesspolicy has no affect on javascript. Most (maybe all?) modern browsers will prevent you from running cross-site-scripting, as it is a security risk.
Your alternative is to proxy that site through a file on your own site, like /proxy.php?loadurl=http://theothersite.com
and then call that file via the Javascript, which would be allowed since it is from your domain.