JSFiddle - React, Tailwind, and code Playground

HTML

Press the button to select the pre-formatted text below:
<input type="button" onclick="selectElementContents(document.getElementById('test'))" unselectable="on" value="Select">
<pre id="test">
   Here's some preformatted text
</pre>
More text

JavaScript

function selectElementContents(el) {
    if (window.getSelection && document.createRange) {
        // IE 9 and non-IE
        var range = document.createRange();
        range.selectNodeContents(el);
        var sel = window.getSelection();
        sel.removeAllRanges();
        sel.addRange(range);
    } else if (document.body.createTextRange) {
        // IE < 9
        var textRange = document.body.createTextRange();
        textRange.moveToElementText(el);
        textRange.select();
    }
}