JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" />
CSS
input {
outline: 0;
}
JavaScript
var regx = /^[0-9]{1,6}(\.[0-9]{1,5})?$/;
$('input[type=text]').on('input', function() {
if(regx.test($(this).val())) {
$(this).css('border', '1px solid green');
} else {
$(this).css('border', '1px solid red');
}
});