JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <input type="text" value="" onkeypress="return myfunction(event)" />
</div>

JavaScript

function myfunction(e){
         var p = new RegExp(/^[0-9]+([.][0-9]+)?$/);
         return e.charCode === 0 || p.test(String.fromCharCode(e.charCode));
    }