JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="textbox" value="1.1251112314555" />
<br/>
<input type="button" id="calculate" value="Calculate"/>

JavaScript

//In Javascript
$("#calculate").click(function() {
    var num = parseFloat($("#textbox").val());
    var new_num = $("#textbox").val(num.toFixed(2));
});


// In jQuery
document.getElementById('calculate').onclick = function() {
    var num = parseFloat(document.getElementById('textbox').value);
    var new_num = num.toFixed(2);
    document.getElementById('textbox').value = new_num;
};