Another disable "next" button question

<script type="text/javascript" charset="utf-8">	
	$(document).ready(function() {
 
		// Identify this question
		var thisQuestion = $('#question{QID}');
 
		$('#movenextbtn').hide();
 
		// Check the initial value of the age question
		if($('input.text', thisQuestion).val() != '' && $('input.text', thisQuestion).val() < 18){
			$('#movenextbtn').show();
		}
 
		// A listener on the age question
		$('input.text', thisQuestion).on('keyup change paste', function() {
			setTimeout(function() {
				if($('input.text', thisQuestion).val() != '' && $('input.text', thisQuestion).val() < 18){
					$('#movenextbtn').show();
				}
				else {
					$('#movenextbtn').hide();
				}
			}, 100);
		});		
	});
</script>