Yesterday I spent two hours debugging one of my CGI.pm scripts. I could not figure out why param('myfield') was returning an empty string.

Then I realized that the text field I was calling existed on a different form than the one I was submitting. Yet CGI.pm's param() function did not return an error when I called this non-existent field.

Using CGI.pm there appears to be no way to tell at runtime whether param('myfield') is returning an empty string because:

  1. the user did not enter any response; or

  2. the submitted form does not include form variable by that name.

Is there any way to force CGI.pm to return an error when I call the param() function for a parameter that does not exist?

In reply to Any Way To Distinguish Undef From Empty Parameters When Using CGI.pm's Param() function? by sierrathedog04

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