JSFiddle - React, Tailwind, and code Playground

HTML

<div id="long-content">
    Minions ipsum belloo! Bananaaaa tulaliloo potatoooo gelatooo potatoooo belloo! Para tú. Chasy me want bananaaa! Tulaliloo butt po kass poopayee potatoooo bappleees chasy jiji ti aamoo! Jiji butt ti aamoo! Chasy poopayee gelatooo butt tulaliloo tank yuuu! Bee do bee do bee do. Me want bananaaa! baboiii hahaha poulet tikka masala jeje para tú para tú po kass cdfghhasy. Bappleees potatoooo tank yuuu! Wiiiii. Jiji bee do bee do bee do wiiiii jeje bappleees pepete poopayee tatata bala tu potatoooo pepete bananaaaa. Belloo! uuuhhh baboiii bee do bee do bee do underweaaar aaaaaah bee do bee do bee do. Underweaaar belloo! Poopayee la bodaaa potatoooo bee do bee do bee do wiiiii aaaaaah baboiii pepete para tú.
    <br/>
Para tú gelatooo tulaliloo para tú la bodaaa la bodaaa hana dul sae po kass. Bananaaaa underweaaar bee do bee do bee do jeje. Daa para tú ti aamoo! Gelatooo tank yuuu! Gelatooo daa jeje tatata bala tu gelatooo ti aamoo! Bappleees gelatooo aaaaaah. Tatata bala tu ti aamoo! Para tú poulet tikka masala me want bananaaa! Hana dul sae tatata bala tu bee do bee do bee do.<br/>

Bananaaaa poopayee ti aamoo! Poulet tikka masala para tú bee do bee do bee do para tú bappleees la bodaaa ti aamoo! Chasy. Tank yuuu! poopayee ti aamoo! Jeje ti aamoo! Tulaliloo poopayee underweaaar po kass chasy ti aamoo! Po kass uuuhhh butt daa tatata bala tu bee do bee do bee do. Butt ti aamoo! Hana dul sae bananaaaa po kass. Belloo! jiji aaaaaah aaaaaah. Aaaaaah baboiii bananaaaa jeje aaaaaah bananaaaa.<br/>

Wiiiii jeje jiji ti aamoo! Poulet tikka masala tank yuuu! Uuuhhh. Underweaaar poopayee jeje aaaaaah jiji hahaha potatoooo para tú me want bananaaa! Aaaaaah. Jiji para tú wiiiii hana dul sae gelatooo potatoooo poopayee gelatooo tank yuuu! Bananaaaa. Jiji belloo! Ti aamoo! Hahaha tank yuuu! Butt po kass bananaaaa daa potatoooo. Belloo! pepete potatoooo ti aamoo! Me want bananaaa!<br/>
    
    Minions ipsum belloo! Bananaaaa tulaliloo potatoooo gelatooo...

CSS

.page{
    border:1px solid gray;
    padding: 35px;
    margin: 5px auto;
    height: 780px;
    width: 500px;
    background: #fff;
    box-shadow: 1px 1px 5px #666;
    font-family: sans-serif;
font-size: 13px;
}
body{
    background: #ccc;
}
#long-content{
    padding: 35px;
    margin: 5px auto;
    width: 500px;
    font-family: sans-serif;
font-size: 13px;
}

JavaScript

var pageCount = $('#long-content').height()/800;
var contentLength = $('#long-content').text().length;
var perPageLength = Math.floor(contentLength/pageCount);
var chunks = [];
for(i=0;i<=pageCount;i++){
    chunks.push($('#long-content').text().substring(i*perPageLength,i*perPageLength+perPageLength));
}
var paged = '<div class="page">'+chunks.join('</div><div class="page">')+'</div>';
$('#long-content').html(paged);