Include JS src file in Firefox Chrome Javascript file

To include a Javascript src file in HTML, it's very simple:

<script src="scripts/b.js" type="text/javascript"></script>

However, how to implement above logic in a Chrome js file(XUL missed including b.js).
There is a XPCOM API @mozilla.org/moz/jssubscript-loader;1
Sample:

const subScriptLoader = Components.classes["@mozilla.org/moz/jssubscript-loader;1"].getService(Components.interfaces.mozIJSSubScriptLoader);
 //file:/// path for XPCOM. http:// not support
subScriptLoader.loadSubScript('file:///c:/scripts/b.js', this);

In normal js file(non-chrome), it's also simple.
Sample:

document.write('<script src="scripts/b.js" type="text/javascript"></script>');

This tip is useful for Selenium-IDE enhancement.