Bug 831457 - [Browser] JS prompt does not focus on the field r=benfrancis
(cherry picked from commit 91fa372a293b83e045f26c1834b66c507e2bace0)
Merge pull request #8326 from EverythingMe/xss-fix

[Bug 840442] fix all XSS vulnerabilities [r=crdlc](cherry picked from commit 749a9c74063bbbd86f7318bfdca1e9050e250a3e)