Re: 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.)
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To check if the value is 0, how about :

  if ($CGI->param('fieldname') == 0)...
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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>
[download]

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...
hth...

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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/;
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++ 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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