Clever Geek Handbook

How to pass boolean values ​​between PHP, HTML Forms and Javascript

I have a PHP program that uses HTML forms and uses JavaScript for validation. There's a hidden field in an HTML form containing a boolean value that is set by PHP, checked when JavaScript is submitted, and passed to another PHP page.

When I tried to use PHP booleans to set the value of an HTML field, JavaScript evaluated it as empty, so I used those and zeros and compared them numerically instead, and now it works fine.

My question is, what is the best practice in this scenario? How do I get JavaScript to read the true / false value in my PHP hidden HTML field without using those and zeros? Or is it just a bad idea?

+3


source to share


2 answers


The good news is that PHP and JavaScript have a similar idea of ​​which values ​​are true and false.

  • An empty string will be false on both sides. A string with something in it (except 0

    in PHP) will be true on both sides.
  • The number 0

    will be false on both sides. All other numbers will be true on both sides.


Since form values ​​will always be strings, as Quentin pointed out in his answer, it might be good practice to use an empty string as a false value and something else (for example 'true'

) as a true value. But I think your way of using 0

and 1

and testing numeric values ​​is the safest approach because it is not misleading. (When someone sees it 'true'

, they might think that would 'false'

also be used for a false value.

+4


source


The value of the form control will always be a string.

If you want boolean then you need to code it somehow and then parse it somehow.



Using 0 or 1 is a great approach. You can also use true

and false

(which you could generate with json_encode

PHP side) and run the value through JSON.parse

. There are many other options in similar directions.

+2


source






More articles:


All Articles