Can a form use ( is_numeric)or(is_string) ??

[Phpfanboi]

<FORM METHOD=POST ACTION="">
<p>Breeder or Business Name<br />
<input type = "text" name = "breedername" size= "25" maxlength = "50" />
</p>
<p>Breeder Telephone<br />
<input type = "text" name = "breedertelephone" size= "25" maxlength = "50" />
</p>
<p>Breeder Location<br />
<input type = "text" name = "breederlocation" size= "25" maxlength = "50" />
</p>
<p>Breeder Desription<br />
<input type = "text" name = "breederdescription" size= "25" maxlength = "50" />
</p>
<p>Leave blank<br />
<input type = "text" name = "breederverify" size= "5" maxlength = "5" /><br /><br />
</p>
<input type="submit" value="Submit" name='submit' />
<br />  <br />
</form>

 <?php
if (is_string($breederverify)) {                                                 <-- If $breederverify is set , then echo "Please leave the lowest box empty!"
echo "Please leave the lowest box empty!";
} else {                                                                     <-- else if $breederverify is unsigned/null execute this block.
$con = mysql_connect("localhost","xxxxxxxxxx","xxxxxxxxxx");

mysql_select_db("cichlid",$con);

$breedername = $_POST['breedername'];
$breedertelephone = $_POST['breedertelephone'];
$breederlocation = $_POST ['breederlocation'];
$breederdescription = $_POST ['breederdescription'];
$breederverify = $_POST ['breederverify'];

$sql = "INSERT INTO breedersinfo SET breederNAME = '$breedername' , breederTELEPHONE = '$breedertelephone' , breederLOCATION = '$breederlocation' , breederDESCRIPTION =                '$breederdescription'";

if(!mysql_query($sql,$con))
{
die('ERROR:Could not connect ' . mysql_error ());
}
echo "";
	  
mysql_close ($con) ;


}

?>

 

 

 

 

 

 

 

 

 

All i am trying to accomplish is a form field that will only update records if the last

$breederverify = $_POST ['breederverify'];

is null/unasigned . I was thinking in order to do this i could use is_numeric , or is_string function to check $var ,to see what it's state is. Any help or advice would be appreciated , provided this is even possible. Cheers guys .

[litebearer]

yes, you can check that server-side

to check it client-side you would need to incorporate some javascript

[AbraCadaver]

Posted values are always strings even if they are empty strings, but it also may be 0 which is considered empty.  Use this:

 

if (!empty($breederverify) || $breederverify == '0') {
    echo "Please leave the lowest box empty!";

[Phpfanboi]

Posted values are always strings even if they are empty strings, but it also may be 0 which is considered empty.  Use this:

 

if (!empty($breederverify) || $breederverify == '0') {
    echo "Please leave the lowest box empty!";

Cheers Mate