What are some common debugging techniques for resolving issues with PHP scripts that generate calendar displays?

Issue: One common issue with PHP scripts that generate calendar displays is incorrect date formatting, which can result in the calendar not displaying the correct dates or not displaying any dates at all. To resolve this issue, ensure that the date format used in the script matches the format of the dates being passed to it.

// Incorrect date formatting
$date = "2022-01-01";
$formatted_date = date("m/d/Y", strtotime($date));
echo $formatted_date;
```

```php
// Correct date formatting
$date = "2022-01-01";
$formatted_date = date("Y-m-d", strtotime($date));
echo $formatted_date;