Correct code for alerting user that form is improperly filled out.

[xcandiottix]

$me = 'cheese';

if(preg_replace('/[a-zA-Z0-9]/', '', $me)){

  echo "Bad Characters";

}

else

{

  echo "Passed";

}

 

-Keep getting it passed when the string cheese has letters in it which should fail the test. Any thoughts?

[Karlos94]

Maybe you are looking for the preg_match() function instead of the preg_replace(). What your doing is if the preg_replace() function returns true (replacing your letters with nothing), it will echo out bad characters.

[xcandiottix]

No, preg_match() gets me a "Passed" result, too. Match does make more sense though, I'll try running with it.

[codebyren]

Your code didn't work like I expected it to either...  But I've never actually used preg_replace so that's not saying much.

 

You could try:

 

$string = 'cheese';
$pattern = '/[a-zA-Z0-9]/';
echo preg_match($pattern, $string) ? 'matched' : 'not matched';

This will show that the string matched.

 

Hope it helps.

[xcandiottix]

behicthebuilder, thank you very much. This worked very well. 

 

$pattern = '/[~!#$%^&*()+=|:";\'<>,/*+]/';
$check = preg_match($pattern, $a) ? 1 : 0;
if ($check == 1){
$error = true;
$status = "Please only use Alphanumeric characters (A-Z, a-z, 0-9). Underscores and dashes are allowed (_,-).";
}
if ($check == 0){
//no illegal characerts found
}

 

Now, in my blocked characters list, would anyone know how could I add {}[] without the script thinking that i'm closing the encapsulating [ ]'s ?

 

 

[jcbones]

Escape them with a slash ( \ ).

 

If you are going to that trouble, why not just check to see if the string contains only alphaNumeric + underscore and dashes.

 

$pattern = '~^[a-zA-Z0-9\s_\-]+$~'; //Matches any string with spaces, underscore, dashes, or alphanumeric.

[xcandiottix]

I've tried to find a good how-to for how to add characters to this but I haven't had luck. Even what you posted:

 

'~^[a-zA-Z0-9\s_\-]+$~'

 

Why 2 ~, why come in brackets and others not, why \s_ ?

 

I'm having problems grasping the logic of this statement  :-\

 

On the other hand! I followed your advice and checking to make sure that the fields only contain your string. Which works fine. I just hate to not understand why it works.

 

Thanks!

[jcbones]

The (~) is de-limiters, It is like yours except you are using slashes.  Only when delimiting the slashes, you must escape the escaping slash.  Just adds more slashes, like (\\{).

 

I'm probably not being clear.

 

Explanation of the string.

~ delimiter

^ matches beginning of string

[] encloses a set.

a-z matches any lowercase alpha character

A-Z matches any uppercase alpha character

\s matches any space

_ matches any underscore

\- matches any dash

+ matches 1 or more of the previous expression

$ matches the end of the string

~ ending delimiter.

[xcandiottix]

Ahh that's great. Very clear, I understand that. That'll be notepadded for sure 

 

Thanks very much