Add example with date

example/sample/date.php

@@ -0,0 +1,45 @@
+<?php
+
+// Get incoming date and its timestamp
+$incomingDate      = $_GET["date"] ?? date("Y-m-d");
+$incomingTimestamp = strtotime($incomingDate);
+
+// Find the first day in the month, and its timestamp
+$firstDayInMonth = date("Y-m-01", $incomingTimestamp);
+$firstDayInMonthTimestamp = strtotime($firstDayInMonth);
+
+// Weekday for the first day in the month (just checking)
+$firstDayInMonthWeekday = date("N", $firstDayInMonthTimestamp);
+
+// The monday to start with, and its timestamp
+$firstMondayTimestamp = strtotime("Monday this week", $firstDayInMonthTimestamp);
+$firstMonday = date("Y-d-m", $firstMondayTimestamp);
+$firstMondayWeekday = date("N", $firstMondayTimestamp);
+
+// Previous and next month
+$previousMonth = date('Y-m-d', strtotime("first day of previous month", $incomingTimestamp));
+$nextMonth = date('Y-m-d', strtotime("first day of next month", $incomingTimestamp));
+
+
+?><style>
+th { text-align: left } 
+</style>
+<form>
+    <input type="date" name="date" value="<?= htmlentities($date) ?>">
+    <input type="submit" name="doit" value="Submit">
+</form>
+<table>
+<tr><th>Inkommande (eller default) datum:</th><td><?= $incomingDate ?></td></tr>
+<tr><th>Inkommande timestamp (antal sekunder sedan 1970-01-01):</th><td><?= $incomingTimestamp ?></td></tr>
+<tr><th>Första dagen i månaden:</th><td><?= $firstDayInMonth ?></td></tr>
+<tr><th>Första dagen i månaden (timestamp):</th><td><?= $firstDayInMonthTimestamp ?></td></tr>
+<tr><th>Första dagen i månaden (veckodag):</th><td><?= $firstDayInMonthWeekday ?></td></tr>
+<tr><th>Första måndagen:</th><td><?= $firstMonday ?></td></tr>
+<tr><th>Första måndagen (timestamp):</th><td><?= $firstMondayTimestamp ?></td></tr>
+<tr><th>Första måndagen (veckodag):</th><td><?= $firstMondayWeekday ?></td></tr>
+</table>
+
+<p>
+    <a href="?date=<?= htmlentities($previousMonth) ?>">Previous month</a> |
+    <a href="?date=<?= htmlentities($nextMonth) ?>">Next month</a>
+</p>