JSFiddle - React, Tailwind, and code Playground

HTML

<body>
  <textarea id="ta1"></textarea>
  <textarea id="ta2"></textarea>
</body>

JavaScript

function ex(){ 
  var text = document.getElementById('ta1').value;
  var resultarea = document.getElementById('ta2');
  var texts=[];
while(text.length>3){ 
     var i=text.indexOf(' ',80);
     if(i<=0)i=text.length;
     var temp = text.slice(0,i);
     text=text.slice(i+1);
     texts[texts.length]=temp;
  }
  for(var i=0;i!=texts.length;i++){
   resultarea.value+='\r\n\r\n'+texts[i]; 
  }
}

var t=document.createElement('button');
t.onclick=ex;
document.body.appendChild(t);