Function cleanup

vm/ByteCodeTranslator/src/javascript/browser_bridge.js:1894–1899

()

        resolve({ ok: ok ? 1 : 0, error: msg == null ? null : String(msg) });
      };
      var cleanup = function() {
        if (cleaned) { return; }
        cleaned = true;
        try { if (urlApi && url) { urlApi.revokeObjectURL(url); } } catch (e) {}
        try { if (iframe && iframe.parentNode) { iframe.parentNode.removeChild(iframe); } } catch (e) {}
      };
      iframe = doc.createElement('iframe');
      // Off-screen but laid out and rendered. A zero-size or visibility:hidden
      // iframe prints blank in several browsers (the "white page" symptom).