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Demo

In this demo you will see how CF_Param assigns a default value to a variable when an incorrect type is specified.

First, lets take a look at <cfparam> and its drawbacks. In this example, we have a URL variable called PageID that needs to be of type numeric.

<cfparam name="url.PageID" default="0">
	
	<cfquery name="getPage">
	SELECT *
	FROM Pages
	WHERE PageID = #url.PageID#
	</cfquery>

As you can see, if url.PageID is not a number, an error will be thrown in the query. This is not ideal as valuable database information could be given away. This is where CF_Param comes in.

<CF_Param VarName="url.PageID" Default="0">
	
	<cfquery name="getPage">
	SELECT *
	FROM Pages
	WHERE PageID = #url.PageID#
	</cfquery>

Here, if url.PageID is not a number, it will get the default of 0. Perfect! Want to see an example?

PageID = 0

Click here to reload this page with a PageID of 10. The value above should be 10.

Click here to reload this page with a PageID of test. The value above should be 0, since that is the default value when a non-numeric value is passed.

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