JSFiddle - React, Tailwind, and code Playground

by Daan De Smedt

HTML

<input type="text" class="textfield" value="" id="extra7" name="extra7" onkeypress="return isNumber(event, this) && maxlength(event, this, 5);" />

JavaScript

function isNumber(evt){
    evt = (evt) ? evt : window.event;
    var charCode = (evt.which) ? evt.which : evt.keyCode;
    if (charCode > 31 && (charCode < 48 || charCode > 57)) {
        return false;
    }
    return true;
}

function maxlength(evt, element, lengthLimit){
    return (element.value.length < lengthLimit);
}