JSFiddle - React, Tailwind, and code Playground

HTML

<script>
	window.___gcfg = {
		parsetags: 'explicit'
	};
</script>
<script src="https://apis.google.com/js/platform.js"></script>
    
<div id="googleClassroomShareButton">
    <div class="g-sharetoclassroom" data-size="64" data-url="http://zapt.io/tdklfajd"></div>

    <button type="button" onclick="renderWidget()">Render Widget</button>
    
    <br>
        <h4>Problem: on Firefox (edge) and IE10, renderWidget() crashes because gapi.sharetoclassroom is not defined.</h4>
        <p>gapi is defined, and gapi.share is defined, but gapi.sharetoclassroom is not.</p>

JavaScript

window.renderWidget = function() {
    gapi.sharetoclassroom.go('googleClassroomShareButton');
};