JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://editor.mestrelab.com/moleculeEditor/MolEditorExport/MolEditorExport.nocache.js"></script>
<div id="editor"></div>
<input type="button" onclick="show()" value="Show Image (Default Margin)"/>
<input type="button" onclick="getMoleculeFormula()" value="moleculeFormula"/>
<input type="button" onclick="getAverageMass()" value="averageMass"/>
<input type="button" onclick="getMonoisotopicMass()" value="monoisotopicMass"/>
<br/>
<img id="image"></img>

JavaScript

var a =null;

function jscOnLoad(){
		 a =new  mestrelab.JsMoleculeEditor('editor',400,200,'true');
}
	
function show(){
		if (a != null)
			document.getElementById('image').src = a.exportImage(400,200);//width , height
		else
			alert("Variable null");
}
function getMoleculeFormula(){
		if (a != null)
			alert(a.getMoleculeFormula());
		else
			alert("Variable null");
	}
	
function getAverageMass(){
		if (a != null)
			alert(a.getAverageMass());
		else
			alert("Variable null");
}

function getMonoisotopicMass(){
		if (a != null)
			alert(a.getMonoisotopicMass());
		else
			alert("Variable null");
}