CODEWITHSUNDEEP
coldfusion
user4409158
user4409158

Reputation:

ColdFusion checking empty form fields

I am very new to ColdFusion and was curious if someone could tell me how to check to see if a form field is empty or not.

For example let's say we set it up like this:

<cfinput 
  type="text" 
  name="firstName"
  id="firstName" 
  value="#form.firstName#"
>

How do I call this later to use it in another form? I tried many things but I am missing something somewhere.

<cfif (form.firstName) EQ 0>

Upvotes: 3

Views: 11225

Answers (4)

James A Mohler
James A Mohler

Reputation: 11120

Some developers prefer checking for emptiness by checking comparing against an empty string. See len(x) better or x NEQ "" better in CFML? 

<cfif trim(form.firstName) NEQ "">

<cfscript> is also an option 

<cfscript>
    if (trim(form.firstName) != "") {
       ...

Yoda conditions work too

<cfscript>
    if ( "" != trim(form.firstName)) {

Upvotes: 2

David Brierton
David Brierton

Reputation: 7397

The most straightforward way is:

<cfif form.firstName IS "">

It simply checks to see if the specified form field is an empty string ("").

Another way of writing the same thing would be:

<cfif len(form.firstName) EQ 0>

This checks to see if the length of the form field value is 0 (empty string). This second method can be shortened a little bit?

<cfif len(form.firstName)>

Assume that form.firstName is empty. This would then become . In boolean evaluation, 0 is false. Assuming the value was not empty, it would become . A non-zero number evaluates to true.

Upvotes: 3

Mitch
Mitch

Reputation: 544

I have always use a two fold check. IsDefined evaluates a string value to determine whether the variable named in it exists. 

<CFIF NOT IsDefined("FORM.firstname") OR 
      FORM.firstname EQ "">

Reference: http://help.adobe.com/livedocs/coldfusion/8/htmldocs/help.html?content=functions_in-k_14.html

Upvotes: 7

Matt Busche
Matt Busche

Reputation: 14333

You can check if the length of the field is 0, using trim would remove any leading or trailing spaces.

<cfif len(trim(form.firstName)) EQ 0>

Upvotes: 14

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