If a ColdFusion variable exists it will have a value. The closest you'll get to a NULL is an empty string.
With that in mind, you can test to see whether a variable is defined or not using isDefined().
<cfif isDefined('myvar')>
</cfif>
Note the quotes around the variable name that is being tested.
You can test whether a variable has a value in a number of ways depending on the variable in question, but quite often you will want to test to see if it has any length:
<cfif len(myvar)>
</cfif>
You may also want to do additional checks on variables such as boolean URL variables:
<cfif isDefined('url.logout') AND isBoolean(url.logout) AND url.logout>
<!--- Your logout code goes here --->
</cfif>Spike
Andrew Dickinson wrote:
I don't think I covered this question last time I asked about Is Null.
How can I express a command like
<CFIF Var IS NULL>
?
This syntax is allowed inside SQL, but I need to do this or something like it in CF. I'm still playing around with the results of left/right joins.
And while I'm at it, will someone please tell me how to search/access the CFAussie archives ? I've had several goes at it, and never managed a non-nil result.
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