note 30372 modified in faq.html by vrana

I do not think you are right about not being able to specify something for the value attribute, but I can see where you would have thought it would fail: A fair warning about testing to see if a variable exists... when it comes to strings, the values '' and '0' are interpreted as false when tested this way... <?php if ($string) { ... } //false for $string == ‘’ || $string == ‘0’ ?> The best practice for testing to see if you received a variable from the form (which in the case of a checkbox, only happens when it is checked) is to test using this... <?php if ( isSet($string) ) { ... } //true if and only if the variable is set ?> The function tests to see if the variable has been set, regardless of its contents. By the way, if anyone's curious, when you do make a checkbox without specifying the value attribute, the value sent from the form for that checkbox becomes “on”. (That's for HTML in general, not PHP-specific). --was-- I do not think you are right about not being able to specify something for the value attribute, but I can see where you would have thought it would fail: A fair warning about testing to see if a variable exists... when it comes to strings, the values '' and '0' are interpreted as false when tested this way... if ($string) { ... } //false for $string == ‘’ || $string == ‘0’ The best practice for testing to see if you received a variable from the form (which in the case of a checkbox, only happens when it is checked) is to test using this... if ( isSet($string) ) { ... } //true if and only if the variable is set The function tests to see if the variable has been set, regardless of its contents. By the way, if anyone's curious, when you do make a checkbox without specifying the value attribute, the value sent from the form for that checkbox becomes “on”. (That's for HTML in general, not PHP-specific). http://php.net/manual/en/faq.html.php