Php check which checkboxes are checked

Form labels should have a for attribute that correspond with the ID of the input element that they are associated with. You can either use empty , or isset. It does not really matter, as long as you understand behavioral differences.

Learn about isset which is a built in "function" that can be used in if statements to tell if a variable has been used or set.

The secret is just update all VALUES first in this case to 0 , and since the will only send the checked values, that means everything you get should be set to 1, so everything you get set it to 1. How to read if a checkbox is checked in PHP? JavaScript can determine whether or not certain ones are checked. That's because JavaScript is running on the same page as the form. However, some browsers don't run JavaScript, and neither do robots. Only the submitted form field names and values exist for the script.

Unchecked checkboxes and radio buttons aren't submitted. The PHP script the form is submitted to can be made to test form field values. Upon encountering an error, processing can be halted or an error message presented to the user. This article presents a way to test whether or not certain checkboxes or radio buttons have been checked.

Because the field names of unchecked checkboxes and radio buttons don't exist for the PHP script, the script will spawn a "doesn't exist" warning if coded to test for values of unchecked checkboxes and radio buttons. Tip: For some spam prevention, the values of the checked checkboxes and radio buttons can be verified in the PHP script to contain the values as coded in the form.

If different, the form submission almost certainly is spam. To code a test for the existence of certain field names, the checkbox and radio field names must be known.

Testing can be done with the PHP empty function:. Here is a working example using the above code with the earlier presented example checkbox field.

It's presented in an iframe to show the results without reloading this page. Does the 'Value1' change if the box is checked? Zend Framework use a nice hack on checkboxes, which you can also do yourself: Every checkbox generated is associated with a hidden field of the same name, placed just before the checkbox, and with a value of "0".

Chuck Le Butt I also noticed about that, but I feel safe to use it: Zend Framework does it too! This is interesting. But is there a tiny possibility that the user agent might submit the first value instead of the last, assuming the checkbox is checked? Sorry, could someone explain me how does it work?

I didn't understand. When it's checked it is transmitted, and will overwrite the hidden value. Show 1 more comment. Gautam Gautam Hammad Khan Hammad Khan ProGrammer 1 1 gold badge 10 10 silver badges 25 25 bronze badges. John Parker John Parker Venkateshwaran Selvaraj 1, 8 8 gold badges 26 26 silver badges 57 57 bronze badges. Example is PHP but applies for everything. Have fun :. Hiram Hiram 2, 1 1 gold badge 14 14 silver badges 13 13 bronze badges. Mazz Mazz 1, 22 22 silver badges 38 38 bronze badges.