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copied!<p>You are trying to access a variable that was created in the global scope from within a function.</p> <p>Either pass the <code>$conn</code> variable in as an argument to the function (this is the prefered option), or use the <a href="http://php.net/manual/en/language.variables.scope.php" rel="nofollow"><code>global</code> keyword</a> to import it into the function's scope.</p> <p>So you could do: <em>(prefered option)</em></p> <pre><code>function validate_details ($conn, $user, $pass) { // function code goes here } // Call the function like this $result = validate_details($conn, 'myuser', 'mypass'); </code></pre> <p>...or this... <em>(not so good)</em></p> <pre><code>function validate_details ($user, $pass) { global $conn; // function code goes here } </code></pre> <p>There are many reasons it is better to pass the connection object in as a parameter, but here are a couple:</p> <ul> <li>It means you can use your function with more that one connection in the same script</li> <li>It means you can easily recycle the function, unmodified, in other scripts</li> <li>If at some point you need to rename the <code>$conn</code> variable in the global scope, you don't have to worry about changing it in the function</li> </ul> <p>I suppose it's also worth mentioning the <a href="http://php.net/manual/en/reserved.variables.globals.php" rel="nofollow"><code>$GLOBALS</code></a> array - this is a <a href="http://www.php.net/manual/en/language.variables.superglobals.php" rel="nofollow">superglobal</a> (i.e. it is available everywhere) that you could use instead, but in practice this is not much different from the <code>global</code> keyword and should generally be avoided for the same reasons.</p> <p>You could use it like this:</p> <pre><code>function validate_details ($user, $pass) { // ... $result = $GLOBALS['conn']->query($sql); // ... } </code></pre>

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