Does Firefox support enablePrivilege("UniversalBrowserRead")?

I have written a plugin which queries webpage parameter from FireFox browser using NPAPI, but whenever I tried to query a webpage having iFrames, I'm getting error while trying to query the innerheight from my plugin: permission denied to query innerHeight I thought it would be cross-domain security rerstriction so I thought of running the following JavaScript code from my plugin using `NPN_evaluate()` function before querying information: ``` netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead"); ``` My question is does Firefox latest version support this JavaScript and will it allow me to query the information?