I want to create a navigation bar similar to this site's:

http://www.mysupermarket.co.uk/#/shelves/top_offers_in_asda.html

Can anyone tell me how to create that navigation bar, which follows you as you scroll the page down, but not following you at the initial loading of page?

When you access to the given website, try to scrolling down and you will understand what I am talking about. The navigation bar that consists of MY SHOP, OFFERS, IDEAS & LIFESTYLE, BAKERY and so-on...

I have really no idea what it's called. At least tell me what it's called, so I'll be able to search.

Here is the solution I've done

window.onscroll = function(){

    if(getScrollTop()>140) {

        document.getElementById(menu).style.position=fixed;

    } else {

        document.getElementById(menu).style.position=;

    }

}



function getScrollTop() {

    if (window.onscroll) {

        // Most browsers

        return window.pageYOffset;

    }



    var d = document.documentElement;

    if (d.clientHeight) {

        // IE in standards mode

        return d.scrollTop;

    }



    // IE in quirks mode

    return document.body.scrollTop;

}