JSFiddle - React, Tailwind, and code Playground

HTML

<input></input>

JavaScript

var regex = /^\d{1,4}(?:\.\d{0,3})?$/;
$("input").keypress(function (e) {
var key = String.fromCharCode(!e.charCode ? e.which : e.charCode);
if (!regex.test($("input").val() + key)) {
    e.preventDefault ? e.preventDefault() : e.returnValue = false;
}
});