JSFiddle - React, Tailwind, and code Playground

HTML

<input type="textbox" name="mynumber">

JavaScript

var A = 1970;
var B= 2017;
$('[name="mynumber"]').keyup(function () {
    if (isInt($(this).val(), 10) < A ) {
        alert("musst be between 1970 and 2017");
    } 
    }
);