JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" onkeypress="return isNumberKey(event)" />

JavaScript

function count_appearance(mainStr, searchFor) {
    return (mainStr.split(searchFor).length - 1);
}
function isNumberKey(evt)
{
    $return = true;
    var charCode = (evt.which) ? evt.which : event.keyCode;
    if (charCode != 46 && charCode > 31
            && (charCode < 48 || charCode > 57))
        $return = false;
    $val = $(evt.originalTarget).val();
    if (charCode == 46) {
        if (count_appearance($val, '.') > 0) {
            $return = false;
        }
        if ($val.length == 0) {
            $return = false;
        }
    }
    return $return;
}