How to handle common code in multiple HTML's using javascript or jQuery

Question

I have an application which has almost 30 html\'s and they share some common code to which i f i made any changes i need to change it on every page. Below is the piece of code w

Answer 1

If you use php you can have that code in one single file and use include 'filename.php';

http://php.net/manual/en/function.include.php