JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="test1" rows="6">a
b
c
d</textarea>

<textarea id="test2" rows="6">a
b
c
d
e
f
g
h</textarea>

JavaScript

function has_scrollbar(elem_id) 
{ 
    elem = document.getElementById(elem_id); 
    if (elem.clientHeight < elem.scrollHeight)
        alert("The element #" + elem_id + " has a vertical scrollbar!"); 
    else
        alert("The element #" + elem_id + " doesn't have a vertical scrollbar."); 
}

has_scrollbar("test1");
has_scrollbar("test2");