Multiple conditions in PHP

Question

I know this is embarrassing easy but I cannot get this to work right now, keep getting syntax errors, I just added in a jquery code that pre-fills in a form filed and when you select the form field it will clear the default value. The result though is if a user submits the form without changing the default value, I need to see if it exist in addition to my normal string sanitations

In this snippet below of PHP I need to run 2 conditions on $fname but below will not work, can someone help please

$fname = 'first name';

if (trim($fname) == '') && ($fname != 'first name') {
    $err .= "error";
}else{
    $err .= "all good";
}

---

For karim79 this code below from your example, exactly like this gives me this error

Fatal Error: Can't use function return value in write context on line 5

<?PHP
$fname = '';

if(empty(trim($fname))) {
    echo "First name is empty";
}
?>

Answer 1

$fname = 'first name';

if (trim($fname) == '' || $fname != 'first name') {
    $err .= "error";
} else {
    $err .= "all good";
}

I would prefer to use strcmp:

if (trim($fname) == '' || strcmp($fname,'first name') !== 0) {
    $err .= "error";
} else {
    $err .= "all good";
}

If the case of the first name is not important, you should consider using strcasecmp instead. Also note you can use empty to test for the empty string:

$fname = '';
$fname = trim($fname);
if(empty($fname)) {
    echo "First name is empty";
} else {
    echo "Not empty";
}

When using empty, beware the following (from the manual):

Note: empty() only checks variables as anything else will result in a parse error. In other words, the following will not work: empty(trim($name)).

Answer 2

$fname = 'first name';

if (trim($fname) == '' || $fname == 'first name') {
    $err .= "error";
}else{
    $err .= "all good";
}

PS: I assumed you want to raise an error if the string is either empty or the standard value. If that's wrong let me know.

Answer 3

I would NOT recommend using empty() for anything. It has some tricky return patterns, including telling you that a 0 is empty, and things of that nature. This, unfortunately, is a shortcoming of PHP.

Instead, try this algorithm (The following assumes your form POSTs):

<?php
    $err = array();
    // this is for sticklers..with E_STRICT on, PHP
    // complains about uninitialized indexes
    if( isset($_POST['name']) )
    {
       $name = trim($_POST['name']);
    }
    else
    {
       $name = '';
    }

    if( strlen($name) == 0 )
    {
      $err[] = "First name is required.";
    }

    // after validation is complete....
    if( count($err) > 0 )
    {
        echo "There are errors!";
        // probably something more elaborate here, like 
        // outputting an ordered list to display each error
        print_r($err);
    }
    else
    {
        echo "It's all good!";
    }
?>