addTab( URL, referrerURI, charset, postData, owner, allowThirdPartyFixup )
addTab( URL, {referrerURI: ..., charset: ..., postData: ..., owner: ..., allowThirdPartyFixup: ..., relatedToCurrent: ... })
tab
elementThe second form of this method was added in Firefox 3.6; it allows you to specify the parameters by name, in any order. It also adds the relatedToCurrent parameter; Firefox uses this to decide whether the new tab should be inserted next to the current tab.