Function Updated 17 Oct 2026

`isNull(value)`

Checks if specified value is null. Useful for null-checks in form validation or before-write checks.

Parameters

valueanyrequired

The value to check.

true if the value is null or undefined, otherwise false. An empty string and 0 give false.

Mixed HTML (or any text file) with inline JavaScript between hash signs.

<p>
    Is value1 null?
    #docly.isNull(value1) ? "Yes" : "No"#
</p>
<p>
    Is value2 null?
    #docly.isNull(value2) ? "Yes" : "No"#
</p>

The template above produces this output:

<p>
    Is value1 null?
    No
</p>
<p>
    Is value2 null?
    Yes
</p>

Normal JavaScript, running in the browser or on the Docly™ server.

write(docly.isNull(null));
write("\n");
write(docly.isNull("hello"));
/* Expected output:
true
false
*/

The JavaScript above produces this output:

true
false

The data the example runs with:

{
    "value1" : "asdf",
    "value2" : null
}