Which of the following methods is not a valid Array object method in JavaScript?

What's the output? var str = 'Example, JavaScript, Test'; var res = str.substring(6,15); document.write(res);

What will the function NaN return for the condition NaN == NaN?

Which statement regarding let in JavaScript is not correct?

In relation to JavaScript prototype, which method is used for returning an array of all own property names?

How can a post ID be retrieved from the permalink?

Which code snippet will create plugins back-end page without showing it as menu item?

Which functions are used to add administration menu item in WordPress ?

Which will correctly add custom mod rewrite rules to .htaccess from a WordPress plugin?

Which code snippet can be used to create custom POST status in wordpress 3.0 +?