简单的“大于”表格验证

Question

I am trying to validate my registration form, and one of my validations doesn't work. I want to echo a error message if the first name is over 20 characters long. I am using the code

} else if($_POST["mem_first_name"] >20) {
        $errors[] = 'Sorry but your First name is limited to 20 Characters each';
}

However no error is shown if more than 20 characters are entered. However if I use the same code but change it to less than like this

} else if($_POST["mem_first_name"] <20) {
        $errors[] = 'Sorry but your First name is limited to 20 Characters each';
}

Then it works, is there a simple fix?

Answer 1

if(strlen($_POST["mem_first_name"]) > 20)

Answer 2

Use strlen() function

} else if(strlen($_POST["mem_first_name"]) >20) {
        $errors[] = 'Sorry but your First name is limited to 20 Characters each';
}

Answer 3

How about using the strlen() function, for counting strings? It is stable and appropriate way of counting number of characters IMO

} else if(strlen($_POST["mem_first_name"]) >20) {
        $errors[] = 'Sorry but your First name is limited to 20 Characters each';
}

Answer 4

You have to use strlen() function for string length checks. Also, be aware that if you need multibyte encoding support, you should switch to using mb_strlen() .

var_dump(strlen('bär'));            // int(4) - byte length
var_dump(mb_strlen('bär', 'utf8')); // int(3) - character length