jQuery limit number input to range
http://stackoverflow.com/questions/26653705
by firegroove
HTML
<input id="hop" type="number" value="0" />
JavaScript
$('#hop').on('input', function () {
var value = $(this).val();
if ((value !== '') && (value.indexOf('.') === -1)) {
$(this).val(Math.max(Math.min(value, 90), -90));
}
});