How to use async javascript in expression?

I want to use tradingview widgets embed code, i customized and i used this code in expreesion but it can not be customize , it shows default value. why? Is json format not used in expression? Code below,

<!-- TradingView Widget BEGIN -->
<div class="tradingview-widget-container">
  <div class="tradingview-widget-container__widget"></div>
  <div class="tradingview-widget-copyright"><a href="" rel="noopener" target="_blank"><span class="blue-text"> Bilgi Bandi</span></a>, TradingView tarafindan</div>
  <script type="text/javascript" src="" async>
  "symbols": [
      "description": "btcusdt",
      "proName": "BINANCE:BTCUSDT"
  "colorTheme": "light",
  "isTransparent": false,
  "displayMode": "adaptive",
  "locale": "tr"
<!-- TradingView Widget END -->


I didn't have any problem in using it as you can see in attachment.

Can you describe better your problem.