what does .= do?

[smartalco]

where i work, they are using a set of code they got off some php script site, and one line includes '.=', that line also returns a non-fatal notice, heres the surrounding code

<?phpinclude $_SERVER['DOCUMENT_ROOT'] . '/classes/SQLManagerKiller.php';$sqlManager = new SQLManagerKiller;$depts = $sqlManager->getResults('SELECT id, department FROM perfrep_departments ORDER BY department');foreach($depts as $dept) {	$depts_html .= '<option value="' . $dept[0] . '">' . $dept[1] . '</option>';}

the error says that there is an undefined variable on line 8, im assuming that it means the $dept_html, and its because of the '.=', what does this do? or rather, what do you think its supposed to be from what you see?PS: search .=, '.=', or ".=" in google, it kills it, it doesn't even say 'no results' or the like, it literally shows nothing where the search results normally are

[jesh]

That's the combination concatenate and assignment operator. It's similar to += in java script:java script:

var message = "Here is a ";message += "message.";

PHP

$message = "Here is a ";$message .= "message.";

The script is probably failing because you haven't ever defined $depts_html. You might try something like this:

$depts_html = '';foreach($depts as $dept) {	$depts_html .= '<option value="' . $dept[0] . '">' . $dept[1] . '</option>';}