php's json_decode firefox's javascript compatibility

it appears have something like

var my_var = {"foo" : "bar"};

in javascript (with firefox during least) post php server accept twine like

{foo:"bar",}

on server side. nonetheless json_decode php doesn't trailing ',' miss quotes around 'foo'. there good proceed purify adult viewed json string?

the json vigilant sent drupal way json services.

edit: doubt closed. badly shaped json due badly combined js drupal module