# JSMediaSdk\_Instance not defined

**URL:** <https://devforum.zoom.us/t/jsmediasdk-instance-not-defined/8177>\
**Category:** Web\
**Created:** [February 21, 2020, 9:19am UTC](https://devforum.zoom.us/t/jsmediasdk-instance-not-defined/8177 "2020-02-21T09:19:02Z")\
**Posts on this page:** 1\
**Showing post:** 4

<div class="post-metadata">

**Author:** ![tommy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/tommy/32/72769_2.png) [@tommy](https://devforum.zoom.us/u/tommy)\
**Post date:** [February 25, 2020, 4:28pm UTC](https://devforum.zoom.us/t/jsmediasdk-instance-not-defined/8177/4 "2020-02-25T16:28:29Z")

</div>

Hey @harald.glanzer,

After speaking with our Web SDK engineers, they have suggest you pre load those resource before the join meeting page.

[https://zoom.github.io/sample-app-web/ZoomMtg.html#preLoadWasm](https://zoom.github.io/sample-app-web/ZoomMtg.html#preLoadWasm)

For example:

```js
zoomJSLib='https://source.zoom.us/1.7.0/lib';
zoomJSAVLib='/av'
ZoomMtg.setZoomJSLib(zoomJSLib, zoomJSAVLib);

ZoomMtg.preLoadWasm();
// pre load wasm success: ${zoomJSLib}${zoomJSAVLib}/sharing.wasm
// pre load wasm success: ${zoomJSLib}${zoomJSAVLib}/audio.encode.wasm
// pre load wasm success: ${zoomJSLib}${zoomJSAVLib}/video.decode.wasm
ZoomMtg.prepareJssdk();

// 1. add script to download requirements js file
// for IE
// <script type="text/javascript" src="${zoomJSLib}${zoomJSAVLib}/../webim.min.js"></script>
// <script type="text/javascript" src="${zoomJSLib}${zoomJSAVLib}/js_media_ie.min.js"></script>
// for No IE
// <script type="text/javascript" src="${zoomJSLib}${zoomJSAVLib}/../webim.min.js"></script>
// <script type="text/javascript" src="${zoomJSLib}${zoomJSAVLib}/js_media.min.js"></script>
// 2. add a node which WebSDK use
// <div id="zmmtg-root">
// <div data-reactroot="" class="meeting-app"></div>
// </div>
// react modal auto generation.
// <div class="ReactModalPortal"></div>

```

> [@harald.glanzer](#):
>
> is it possible that this JsMediaSDK\_Instance - error can be triggered by calling ZoomMtg.join() BEFORE ZoomMtg.prepareJssdk(); and / or ZoomMtg.preLoadWasm(); have finished?

Yes that is possible.

Thanks,  
Tommy

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