Textpattern CMS

#1 Yesterday 17:45:35

abu

New Member

From: Switzerland

Registered: 2025-04-03

Posts: 4

Strange variable behavior

Something I simply don’t understand, maybe someone can help me out here.

Take this:

Value of variable is ***<txp:variable name="p" />***

<txp:if_variable name="p" value="0">
	<p>Rendered if variable p == 0</p>
<txp:else />
	<p>Rendered if variable p != 0</p>
</txp:if_variable>

Outputs that:

Value of variable is ***0***

Rendered if variable != 0

Why does this happen?

#2 Yesterday 20:12:44

jakob

Admin

From: Germany

Registered: 2005-01-20

Posts: 4,881

Website GitHub

Re: Strange variable behavior

In other tag attributes, the value "0" traditionally means “off”, so I guess the tag is interpreting 0 as meaning false, so the condition is saying: “if variable p doesn’t exist…”, but as the variable does exist, it’s showing you the other part of the if conditional.

Can you use another value pair, e.g. "on" and "off" or "yes" and "no"? Or if you’re using a variable as a counter, start with "1" …

I was wrong. Testing on the demo page with:

<txp:variable name="p">0</txp:variable>

Value of variable is ***<txp:variable name="p" />***

<txp:if_variable name="p" value="0">
	<p>Rendered if variable p == 0</p>
<txp:else />
	<p>Rendered if variable p != 0</p>
</txp:if_variable>

returns Rendered if variable p == 0.

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#3 Today 08:45:49

abu

New Member

From: Switzerland

Registered: 2025-04-03

Posts: 4

Re: Strange variable behavior

Thank you for your prompt reply.
It was my bad, as mostly. My method for setting the variable using JavaScript didn’t work.