Collapsible menu in the header (mobile web development)

Collapsible menu in the header (mobile web development)

Relative newbie at work here, so keep that in mind please.

I am wondering how I would go about implementing the collapsible menu in the header at work in the following website:


As you can see, the menu collapses below the header when clicked/touched on a mobile device. 

Is there alternative way the menu could drop down? 

Is this considered a good feature to have on a mobile website and if no, what are the better/most popular alternatives?

I am working with Dreamweaver CS6, jquery 1.82 and jquery mobile 1.2
Any advice would be appreciated.