how to save checkbox value into mysql database using php

Question

hi i have a form which has a checkbox and i want to save the value of the checkbox into my database but when i click on the checkbox and save it it works fine and when i try to save the form without checking on the chekbox it shows undefined index can any one help me out

here is my html

<input type="checkbox" name="active" value="1"></input>

here is my php

$nactive  = $_POST["active"];

here is my save part

mysql_query("INSERT INTO `usermain`( `username`, `password`, level, active,`zimname`, zimmob, `email`, admin, makhtab)
            Values
                   ('$nuser', '$npwd', '$nlevel', '$nactive', '$nzname', '$nzmob', '$nemail', '0', '$makh')") or die(mysql_error());

Answer 1

If the checkbox isn't checked, the browser won't actually send the data in your POST request. You'll need to check if the value is set, and then update your variable accordingly.

$inactive = isset($_POST["active"]) ? $_POST["active"] : 0;

Answer 2

If the checkbox is not checked, the value is not posted to the script. You must check if it is set before using it.

if(isset($_POST['active'])){
    //do something if is
}
else{
    //do something if not
}

Answer 3

Use an isset control in the next page like this :

if (!isset($nactive)) $nactive = 0;

If your checkbox isn't checked, the value will be 0