javascript - Using JS (In FF-Pentadactyl), how to get a handle to site content like media players? -

using firefox web console (which can brought control shift k ) can access things flowplayers.

jwplayer().play(), example 

the console offers autocompletion suggestions it. console in kind of, lack of words , knowledge, namespace? tried things like

content.document.getelementsbyname('flvplayer').item(0) 

using pentadactyls js intepreter (accessed :js) seem give me player handle, or @ least prints out <html:object> corresponds it. appending .play() doesn't work, though. it's not function.

what need emulate web-consoles way of doing it?

i realize might spoonfeedy question, if not acceptable i'd still appreciate pointed directions possibly discover solution myself reading.

i tried searching myself terms seem quite ambiguous , results people talking own sites, scripts running inside of 'namespace', not outside trying do. (unless wrong concepts of inside , outside here.)

cheers~~

the following command works me; defines command ypl plays youtube video on page

command! ypl open javascript:(function()     {content.document.getelementbyid('movie_player').playvideo()})() 

another example: defines ytr command takes integer argument , moves current time position of video amount in seconds

command! -nargs=1 ytr open javascript:(function(){var vid =      content.document.getelementbyid('movie_player'); vid.seekto(vid.getcurrenttime() +      (<args>), true)})() 

i hope helps bit. when wrote while ago may have tried :js , if didn't work used :open javascript:....