Checks whether the given value is null or not declared.
A value is null if:
If one of the conditions is fulfilled, isnull() returns true, otherwise false.
- it is a variable or object (field) and is not declared
- it is the null value.
| input:||resulting output:|
<let D=null; ? isnull(D)>
<let D=null; ? isdecl(D)>
<let D=null; ? isempty(D)>
<? isnull(" ")>
<? isempty(" ")>
If it's not obvious how to use this function, imagine that you have a variable named D that has been declared, but has been assigned a null value and another variable U that has not been declared. In contrast to the isdecl() function, isnull() would return true for both variables.
This page was dynamically generated by the
web application development tool RADpage
H.E.I. provides support, tools, and services like
Webdesign in Mannheimm,
the HTML/CSS 3D WebGL Animation Library taccgl,
3D Webdesign, and
3D Product Configurator
(3D Produkt Konfigurator in German).
Selected blog articles :
3D Objects on HTML pages,
CSS Transition Visibility, and
CSS Transition Display.
© 1996-2022 H.E.I. All Rights Reserved.