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Re: zero vs. empty

by screamingeagle (Curate)
on Mar 03, 2002 at 21:40 UTC ( #149018=note: print w/ replies, xml ) Need Help??

in reply to zero vs. empty

you could check if the value returned from CGI->param('fieldname') is empty by using the length function

if length($cgi->param('fieldname')) == 0 (that means the field is empt +y.)
To check if the value is 0, how about :
if ($CGI->param('fieldname') == 0)...
Option 2: if u want to use Javascript, then this might work:
<html <head> <script language="Javascript"> function chkinput(objForm) { if (objForm.inputfield.value == "") { objForm.fld_has_value_or_not.value = "N" } else { objForm.fld_has_value_or_not.value = "Y" } objForm.submit(); return true; } </script> </head> <body> <form name="testfrm" method="post" action="cgifile.cgi" onSubmit="retu +rn chkinput(this);"> <input type=hidden name=fld_has_value_or_not value=""> <input type="text" name="inputfield" value=""> <input type=submit value="Submit"> </form> </body> </html>
in this case, if the input field is empty, the hidden variable will be set to "Y", which can be checked by the cgi file and processed accordingly...

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Re: Re: zero vs. empty
by Juerd (Abbot) on Mar 03, 2002 at 23:06 UTC

    To check if the value is 0, how about :   if ($CGI->param('fieldname') == 0)...

    Keep in mind that "three" == 0. To check if the entered value equals the single character 0, use a string comparison: $something eq '0'.
    It's generally a good idea to warn if the user didn't enter nothing or digits. Or, using reversed logic: warn if a non-digit character is found:

    die "\$foo contains a non-digit character!\n" if $foo =~ /\D/;

    ++ vs lbh qrpbqrq guvf hfvat n ge va Crey :)
    Nabgure bar vs lbh qvq fb jvgubhg ernqvat n znahny svefg.
    -- vs lbh hfrq OFQ pnrfne ;)
        - Whreq

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