Select alle checkboxen (Opgelost)

<form name="email_users" action="send_mail.php" method="post" target="_blank">
					<?php
							$db 	= mysql_connect("localhost","george", "mijn wachtwoord");  
							mysql_select_db("camilstaps_george",$db) or die ("Kan niet verbinden."); 
							
							$sql 	= "SELECT * FROM `klant` ORDER BY login ASC";
							$result = mysql_query($sql);
							$rows	= mysql_num_rows($result);
							echo '<input type="checkbox" id="checkall" OnClick="SelectAll(Document.GetElementsById.sendto,'.$rows.')"><br>';							$a=0;
							while ($row = mysql_fetch_array($result)) {
								$a=$a+1;
								echo '<input id="sendto" type="checkbox" name="sendto" value="'.$a.'">'.$row["login"].'<br>';
							}
					?>
					<input type="submit" class="100px" value="verstuur emails">
				</form>

<script language="JavaScript">
	function SelectAll(sendto,aantal) {
		for (i=0;i<aantal;i++) {
			sendto[i].checked=true;
		}
	}
	</script>

<form name="email_users" action="send_mail.php" method="post" target="_blank">
					<?php
							$db 	= mysql_connect("localhost","george", "mijn wachtwoord");  
							mysql_select_db("camilstaps_george",$db) or die ("Kan niet verbinden."); 
 
							$sql 	= "SELECT * FROM `klant` ORDER BY login ASC";
							$result = mysql_query($sql);
							$rows	= mysql_num_rows($result);
							echo '<input type="checkbox" id="checkall" OnClick="SelectAll(Document.GetElementsById.sendto,'.$rows.')"><br>';							$a=0;
							while ($row = mysql_fetch_array($result)) {
								$a=$a+1;
								echo '<input id="sendto" type="checkbox" name="sendto" value="'.$a.'">'.$row["login"].'<br>';
							}
					?>
					<input type="submit" class="100px" value="verstuur emails">
				</form>
 
<script language="JavaScript">
	function SelectAll(sendto,aantal) {
		for (i=0;i<aantal;i++) {
			sendto[i].checked=true;
		}
	}
	</script>