JavaScript isset() function
44858
JavaScript isset() equivalent
32293
What's the difference between if(!$variable) and if(isset($variable))?
132179
Is  && statement() the same as if() statement()?
89873
PHP: a short cut for isset and !empty?
9122
Setting a function equal a variable?
123380
Built in support for sets in PHP?
127653
Is it possible to implement dynamic getters/setters in JavaScript?
157654
Checking if a key exists in a JavaScript object?
157822
Does a javascript if statement with multiple conditions test all of them?
61752
What's the difference between isset() and array_key_exists()?
37735
How can I check for "undefined" in JavaScript?
155520
Why does $('#id') return true if id doesn't exist?
39947
Checking if a string contains an integer
58046
How to check whether a string contains a substring in JavaScript?
50095
Sending a JavaScript variable to a PHP function
1469
Is there a difference between "==" and "is"?
6971
boolean variable values in PHP to javascript implementation