JSFiddle - React, Tailwind, and code Playground

HTML

<h2>First tile</h2>
<p>First paragraph First paragraph First paragraph First paragraph </p>

<h2>Second title</h2>
<p>Second paragraph Second paragraph Second paragraph Second paragraph</p>

<h2>Third title</h2>
<p>Third paragraph Third paragraph Third paragraph Third paragraph</p>

JavaScript

$.fn.selectTextAll = function() {
    var doc = document,
        numElem = this.length,
        elements = this;
    
    if(doc.body.createTextRange) {
        for(i=0; i<numElem; i++) {
            var range = document.body.createTextRange();
            range.moveToElementText(elements[i]);
            range.select();
        }
    } 
    else if(window.getSelection) {
        var selection = window.getSelection();
        selection.removeAllRanges();
        for(i=0; i<numElem; i++) {
            var range = document.createRange();
            range.selectNodeContents(elements[i]);
            selection.addRange(range);
        }
    }
};

$('h2').selectTextAll();