How to add script for all widgets(like protectedCss)

You can initialize custom js in the canvas in this way:

const editor = grapesjs.init({
  ...
  canvas: {
    scripts: ['https://.../script.js']
  }
});

Thank you. Btw what I want to need is inline javascirpt. not external link... regards.

In that case, I suggest you access the document of the iframe and to append manually the inline script (to get the document use editor.Canvas.getDocument())