Checkbox demo

checkbox.php

<?php
$check = isset($_POST['check']) ? $_POST['check'] : array();

$types = array(
    1 => '報紙', 
	2 => '雜誌', 
	3 => '其他'
);

echo '<h3>',"Checked:",'</h3>';
foreach($check as $value) {
	if (array_key_exists($value, $types) === true) {
		echo "<p>",$types[$value],"</p>";
	}
}

index-must-check-one-1.php

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script>
(function($) {
    $(function() {
		$("form").on('submit', function() {
			if ($('input[name="check[]"]:checked').length <= 0) {
				alert("Please check at least one item");
				return false;
			}
			return true;
		});
	});
})(jQuery);
</script>

<form action="checkbox.php" method="post">
<input type="checkbox" name="check[]" value="雜誌" /> 雜誌
<input type="checkbox" name="check[]" value="報紙" /> 報紙
<input type="checkbox" name="check[]" value="其他" /> 其他
<input type="submit" value="submit">
</form>

index-must-check-one-2.php

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script>
(function($) {
    $(function() {
		$("form").on('submit', function() {
			if ($('input.must_checked').is(':checked') === false) {
				alert("Please check at least one item");
				return false;
			}
			
			
			return true;
		});
	});
})(jQuery);
</script>

<form action="checkbox.php" method="post">
<input type="checkbox" name="check[1]" value="雜誌" class="must_checked" /> 雜誌
<input type="checkbox" name="check[2]" value="報紙" class="must_checked" /> 報紙
<input type="checkbox" name="check[3]" value="其他" class="must_checked" /> 其他
<input type="submit" value="submit">
</form>

index-must-check-one-3-group.php

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script>
(function($) {
    $(function() {
		$("form").on('submit', function() {
			var groupNames = [];
			
			$(".must_checked").each(function() {
				var group = $(this).attr('rel');

				if ($.inArray(group, groupNames) === -1) {
					groupNames.push(group);
				}
			});

			for(var i=0; i<groupNames.length; i++) {
				var groupName = groupNames[i];
				
				if ($("input[rel=" + groupName + "]").is(":checked") === false) {
					alert(groupName + " must as least one checked");
					return false;
				}
			}
		});
	});
})(jQuery);
</script>

<form action="checkbox.php" method="post">
<input type="checkbox" name="check[1]" value="雜誌" rel="group1" class="must_checked" /> 雜誌
<input type="checkbox" name="check[2]" value="報紙" rel="group1" class="must_checked" /> 報紙
<input type="checkbox" name="check[3]" value="其他" rel="group1" class="must_checked" /> 其他

<input type="checkbox" name="check[1]" value="雜誌" rel="group2" class="must_checked" /> 雜誌
<input type="checkbox" name="check[2]" value="報紙" rel="group2" class="must_checked" /> 報紙
<input type="checkbox" name="check[3]" value="其他" rel="group2" class="must_checked" /> 其他
<input type="submit" value="submit">
</form>

index.php

<form action="checkbox.php" method="post">
<input type="checkbox" name="check[]" value="1"> 報紙
<input type="checkbox" name="check[]" value="2"> 雜誌
<input type="checkbox" name="check[]" value="3"> 其他
<input type="submit" value="submit">
</form>