JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text">
<button>testar</button>

JavaScript

function addScript(varname) {
    var script = document.createElement('script');
    script.innerText = 'var ' + varname + ' = 10; alert(' + varname + ');';
    document.body.appendChild(script);
}

var input = document.querySelector('input');
var button = document.querySelector('button');
button.addEventListener('click', function() {
    var name = input.value;
    addScript(name);
});