Making sure a number is entered in a field

[squaringkarma]

How would you validate a form to make sure a user entered in a number for a specific field? I'm blanking on that right now. I'm working on a site where there are 3 different forms depending on what a user inputs for their age. If the user does not enter their age, I want the initial form to reappear with an error of "Please enter your age." Right now, the initial form only appears when the trimmed string length for the field is 0.

[marcus]

Now that I think of it, if you're checking for age you might want to look at http://php.net/ctype_digit or http://php.net/is_int

 

is_numeric will return true for decimal values.

[metrostars]

if(!is_numeric($value))

{

//Value is not numeric

} else {

// Value is numeric

}

[squaringkarma]

Hm thanks. mgallforever, when I try with is_int, I always get false. I presume this is because it's form input and it's reading it as a string. I guess my next question would be how do you convert a string into a number? (Though the ctype_digit is accepting strings as input, so maybe the answer to my question isn't necessary.)

[FD_F]

try use something like this :

$num = "1"; 
$bol = ctype_digit($num);
if ($bol == True)
{
echo "true";
}
else
{
echo "false";
}