JSFiddle - React, Tailwind, and code Playground

HTML

<form action="" method="">
    <input name="title" type="text" maxlength="256" value="daniel"/>
    <input name="description" type="text" maxlength="512" value="awesome"/>
</form>

CSS

input{
    display:block;
    font-size:12px;
}

JavaScript

function resize(elem){
    if(!elem.value.length) elem.size=1;
    else elem.size=elem.value.length;
}


var elem=document.getElementsByTagName('input');
for(i in elem){
    elem[i].addEventListener('keyup', function(){resize(this);}, false);
    resize(elem[i]);
}