JSFiddle - React, Tailwind, and code Playground

HTML

<button type="button" 
onClick="Copy('&lt;button onclick=&quot;myFunction()&quot;&gt;Click me&lt;/button&gt;', false)">
&lt;button onclick=&quot;myFunction()&quot;&gt;Click me&lt;/button&gt;
</button>

<br><br>

<button type="button" 
onClick="Copy('&lt;a href=&quot;tel:000&quot;&lt;CALL: 000&lt;/a&gt;
&lt;button onclick=&quot;&quot;&gt;test&lt;/button&gt;', false)">
&lt;a href=&quot;tel:000&quot;&lt;CALL: 000&lt;/a&gt;
&lt;button onclick=&quot;&quot;&gt;test&lt;/button&gt;

<br><br>

JavaScript

document.addEventListener('DOMContentLoaded', () => {
            document.querySelector('select[name="language"]').onchange = changeEventHandler;
        }, false);

        const changeEventHandler = event => {
            let lang = event.target.value;
            if (!lang)
                return undefined;
            localStorage.setItem('language', `${ lang }`);
        };

        const Copy = (text, withLanguage = false) => {
            let lang = localStorage.getItem('language');
            let dummy = document.createElement('textarea');
            document.body.appendChild(dummy);
            if (withLanguage) {
                dummy.value = `${ text }${ lang ?`${ lang }` : ``}`;
            } else {
                dummy.value = `${text} `;
            }
            dummy.select();
            document.execCommand('copy');
            document.body.removeChild(dummy);
        };