Something

		<?php if (!isset($continue)) { ?>
		<form action="editbox1.php?continue=true" method="post">
		<?php
			$filename = "box1.inc";
			$text = read_file($filename);
		?>
		<textarea id="editor"><?php echo $text; ?></textarea>
		<input type="submit" value="Update Section" />
		</form>
		<?php } else {
			$filename = "box1.inc";
			$cont = $_POST['editor'];
			$r = write_file($filename, $cont);
			echo "done.";
			}
		?>