从外部函数访问变量（PHP）

I am trying to access this variable into function but its give me an error Undefined variable: ERROR.

<?php
$ERROR["emptyEmail"] = "empyt email";
$ERROR["emptyPassword"] = "empty password";

function validateLogin($data) {
    if (empty($data["email"])) {
        return $ERROR["emptyEmail"];
    } else if (empty($data["password"])) {
        return $ERROR["emptyPassword"];
    } else {
        return "valid";
    }
}
?>

Insert inside the function:

global $ERROR;

So, the variable can be accessed inside the function scope (see global keyword).

function validateLogin($data) {
    global $ERROR;
    ...
}

Alternatively you can access to all variables that are outside the function using $GLOBALS:

    $GLOBALS['ERROR']