x
<html><body><p>The value of a variable with no value is <b>undefined</b>.</p><p>Variables can be emptied by setting the value to <b>null</b>.</p><p id="demo"></p><script>var person;var car = "Volvo";var x = null;document.getElementById("demo").innerHTML =person + "<br>" + car + "<br>" + x;</script></body></html>