javascript - Jquery post response not available -

i'm new javascript, , problem may trivial need help. goal send post python server based on tornado.

in following function :

var machin = $.post( '/room/testroom', function( data ) {          truc = data;          return truc; 

i never content of truc. variable has url inside used create new websocket connection.

when console.dir(machin); see wanted responsetext wanted url in console, i'm not able outside of console.

the variable data inside function has wanted data, if : alert(data) see alert box wanted url.

feel free ask me details may not entirely clear.

server side, python code one:

def post(self, roomname):     print 'je poste'     db = connect(host=config.sqlserver, user=config.sqluser, passwd=config.sqlpass, db=config.sqldb)     cursor = db.cursor()     uri = self.request.uri     url = uri.split('/')     roomname = url[2]     sql = 'select roomid abcd_un roomname = %s', [roomname]     cursor.execute(*sql)     roomid = cursor.fetchone()     print 'roomid', type(roomid)     roomid = str(roomid[0])     roomid = roomid.decode()     fullurl = 'ws://' + self.request.host + '/socket/' + roomid      #print uri     db.close()     wsurl = {         'url': fullurl,     }     wsurl_encoded = tornado.escape.json_encode(wsurl)     self.write(wsurl_encoded) 

try:

var machin = function (){      $.post( '/room/testroom', function( data ) {      truc = json.parse(data);      return truc; } 

now call function:

var response = machin();