Describe the bug
Context: I was giving iWebDJ's demo mixer a try when testing out Ruffle. The preloader is held up at 0% and there's an AVM2 error attached at the console:
`AVM2 error: Error: The stage's loader info does not have parameters ruffle.js:1:24953
__wbg_error_9ff84d33a850b1ef moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
h82ac9def11571311 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4572660
::log::he4dd51a1e974bbb1 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4544165
hba0b0744e005b8cb moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:3899837
h1e5da12cb630e9a8 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:254811
h304da35526ca3339 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:3688230
h3486648f1e7d52a4 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:3079439
::call::h49b188d1817ad986 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:3159053
h432e62e19376ff4d moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:2560508
::run_frame_scripts::hde6c195fc226e3e7 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:2770849
h4be654246a8dce27 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:3821190
hcc9377f967fc44c7 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:1696074
h96fab9296cbfa34d moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4571819
+Output = R as wasm_bindgen::closure::WasmClosure>::describe::invoke::h2a4bc7e130fa01d5 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4541968
S moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
a moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
(Async: FrameRequestCallback)
__wbg_requestAnimationFrame_aa3bab1f9557a4da moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
P moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
hcc9377f967fc44c7 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:1705848
h96fab9296cbfa34d moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4571819
+Output = R as wasm_bindgen::closure::WasmClosure>::describe::invoke::h2a4bc7e130fa01d5 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4541968
S moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
a moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
(Async: FrameRequestCallback)
__wbg_requestAnimationFrame_aa3bab1f9557a4da moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
P moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
hcc9377f967fc44c7 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:1705848
h96fab9296cbfa34d moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4571819
+Output = R as wasm_bindgen::closure::WasmClosure>::describe::invoke::h2a4bc7e130fa01d5 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4541968
S moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
a moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
(Async: FrameRequestCallback)
__wbg_requestAnimationFrame_aa3bab1f9557a4da moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
P moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
hcc9377f967fc44c7 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:1705848
h96fab9296cbfa34d moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4571819
+Output = R as wasm_bindgen::closure::WasmClosure>::describe::invoke::h2a4bc7e130fa01d5 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4541968
S moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
a moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
(Async: FrameRequestCallback)
__wbg_requestAnimationFrame_aa3bab1f9557a4da moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
P moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
hcc9377f967fc44c7 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:1705848
h96fab9296cbfa34d moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4571819
+Output = R as wasm_bindgen::closure::WasmClosure>::describe::invoke::h2a4bc7e130fa01d5 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4541968
S moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
a moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
(Async: FrameRequestCallback)
__wbg_requestAnimationFrame_aa3bab1f9557a4da moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
P moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
hcc9377f967fc44c7 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:1705848
h96fab9296cbfa34d moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4571819
+Output = R as wasm_bindgen::closure::WasmClosure>::describe::invoke::h2a4bc7e130fa01d5 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4541968
S moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
a moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
(Async: FrameRequestCallback)
__wbg_requestAnimationFrame_aa3bab1f9557a4da moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
P moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
hcc9377f967fc44c7 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:1705848
h96fab9296cbfa34d moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4571819
+Output = R as wasm_bindgen::closure::WasmClosure>::describe::invoke::h2a4bc7e130fa01d5 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4541968
S moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
a moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
(Async: FrameRequestCallback)
__wbg_requestAnimationFrame_aa3bab1f9557a4da moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
P moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1
`
Steps: Just go to https://iwebdj.com/demo_djmixer.php (CORRECTED, SORRY) to see the sideloader hold up with Ruffle.
**Expected behavior**
Preloader comes first, and brings in the mixer itself, to automatically choose a track on deck 1.
**Is the problem with the Ruffle desktop app, extension, or self-hosted version?**
Firefox Extension 0.1.0 nightly 2021-04-29
**What platform are you using?**
Windows 10 64 bit 20H2 Firefox Extension
Do let me know if I missed something.
Now fails with TypeError: Error #1009: Cannot access a property or method of a null object reference. (accessing field: http://adobe.com/AS3/2006/builtin::shift).
Describe the bug Context: I was giving iWebDJ's demo mixer a try when testing out Ruffle. The preloader is held up at 0% and there's an AVM2 error attached at the console: `AVM2 error: Error: The stage's loader info does not have parameters ruffle.js:1:24953 __wbg_error_9ff84d33a850b1ef moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/ruffle.js?uniqueMessageSuffix=91220461727:1 h82ac9def11571311 moz-extension://bba2c523-2c56-446e-afa5-98a1e3e04cad/dist/fecfb0991d7f0860b8d4.wasm:4572660