Invalid characters

[user4fun]

Can someone tell mewhatis wrongwith this thingthank you

$junk = array('.' , ',' , '/' , '\' , '`' , ';' , '[' ,  ']' , '-', '_', '*', '&', '^', '%', '$', '#', '@', '!', '~', '+', '(', ')', '|', '{', '}', '<', '>', '?', ':', '"', '='); 			    //starting lenght of username  $len = strlen($_POST['username']);    //replace invalid characters  $_POST['username'] = str_replace($junk, ' ', $_POST['username']);  $test = $_POST['username'];    //if lenghts are different ($len smaller), invalid characters found, so prompt error.  if(strlen($test) != $len) {	 die('Username Error: Username contained invalid characters. You can only use A-Z, 0-9 and the underscore (_).');  }

[user4fun]

When i change the $junkFROM

$junk = array('.' , ',' , '/' , '\' , '`' , ';' , '[' ,  ']' , '-', '_', '*', '&', '^', '%', '$', '#', '@', '!', '~', '+', '(', ')', '|', '{', '}', '<', '>', '?', ':', '"', '=');

TO

$junk = array(''*', '&');

everything works fine but i still need to add all the other junk stufflol

[user4fun]

THIS IS ABNORMALI tried to run each one seperatly and they all work except the '\'this vharacter that i am trying to make invalid does not work for me, i am guessing because it is a sign used in some kind off advance php code above my knowledgeany ideas how to fix this

[reportingsjr]

You need to escape the backslash. The backslash is used to escape characters, so it is escaping the single quotation mark that is after it. Also, in the die() it says you can have the underscore in your name while the underscore is in the list.. And since you replace everything with a space, the strlen test will not work. It will still be the same length. Use this:

$junk = array('.' , ',' , '/' , '\\' , '`' , ';' , '[' ,  ']' , '-', '*', '&', '^', '%', '$', '#', '@', '!', '~', '+', '(', ')', '|', '{', '}', '<', '>', '?', ':', '"', '=');			    //starting lenght of username  $len = strlen($_POST['username']);    //replace invalid characters  $_POST['username'] = str_replace($junk, '', $_POST['username']);  $test = $_POST['username'];    //if lenghts are different ($len smaller), invalid characters found, so prompt error.  if(strlen($test) != $len) {	 die('Username Error: Username contained invalid characters. You can only use A-Z, 0-9 and theunderscore (_).');  }

That should work correctly!

[jesh]

You might also think about learning regular expressions:

if(preg_match("/^[A-Z0-9_]+$/", $_POST['username']){	// username is ok}else{	// username has invalid characters.}

This site has a good tutorial: http://www.regular-expressions.info/tutorial.html

[MrAdam]

Also i'm not sure if you can edit the value of a post variable? (I may well be wrong) But I think it's read only...

[justsomeguy]

You can change anything in $_POST or the other superglobals. It doesn't do anything like send it to the next page, but they are just arrays, you can change the values in them if you want.