<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>You say Yes, I say No</title>
</head>
<body>
<form name="answers">
What is?<input type="text" name="assertion" value="A" onchange="deny()">
<br>
What is not.<input type="text" name="denial" value="A is not A">
</form>
<script>
function deny(){
var fieldOne = document.answers.assertion.value;
var fieldTwo = fieldOne + " is not " + fieldOne;
document.answers.denial.value = fieldTwo;
}
</script>
</body>
</html>