The Logical NOT Operator reverses the logical state of its operand. If a condition is true, then the logical NOT operator will make it false.
<html>
<body>
<script>
var a =true;
document.write("a = ");
document.write(a);
result =!a;
document.write("<br>!a = ");
document.write(result);
</script>
</body>
</html>