How can I check if a checkbox is NOT checked

Question

I need to check whether checkbox is checked or not. Normally I would do it like this:

<?php
    $checked = isset($_POST['checkbox']);
?>

But I don't know what is the name. More at screenshot (I'm using Laravel 4).

Screenshot

Answer 1

You simply can't. The data for unchecked checkboxes are not send to the server.

You could do a workaround with javascript where the JS appends some hidden fields before submit with the nonchecked boxes

Answer 2

Supposedly you should know what the list of checkboxes is/was that you asked the user to check. Checked checkboxes are submitted to the server, unchecked ones aren't. You can calculate the difference between these two lists.

Answer 3

如果您使用的是jquery，并且知道该复选框的ID，则可以使用以下代码进行检测：

var isChecked = $("#cbId").is(":checked");

Answer 4

<?php
if ( ! isset($_POST['checkbox_name']))
{
    "Not checked";
}
?>

Answer 5

If checkbox didn't check - you will not have this variable in $_REQUEST.

<form action="">
<input type="checkbox" name="ch1"/>
<input type="checkbox" name="ch2"/>
<input type="checkbox" checked="checked" name="ch3"/>
<input type="submit" name="Post" value="Post">
</form>

When you click on "Post". In backend you'll see:

<?php
if(isset($_REQUEST['ch1']))
    echo 'ch1 is checked!';
if(isset($_REQUEST['ch2']))
    echo 'ch2 is checked!';
if(isset($_REQUEST['ch3']))
    echo 'ch3 is checked!';
?>

In my case you'll see: "ch3 is checked!".