HTML and CSS header nav bar question

I was playing with bootstrap, doing some tests etc.. I would like instead of using a button in dropdown menu, to use an icon like the icons of glyphicons, when you click on it, you get a dropdown menu, the same idea of facebook, when you click on notification icon, it shows you the menu.. how to achieve that?
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Duy PhamFreelance IT ConsultantCommented:
It's simply a button without label. You can also see that in examples of using glyphicons of Bootstrap:
adra750Author Commented:
so you mean that facebook uses button to dropdown the notifications?

I need more answers, let's wait for other experts
thanks anyway
Duy PhamFreelance IT ConsultantCommented:
It could be button, image or anchor, whatever you want to use. Anchors (<a>) are commonly used (Experts-Exchange, LinkedIn, Facebook, etc.). They are just toggle buttons, used to toggle dropdowns, notificates, menus, or any detailed content blocks that meet your needs.

You can easily see the example here in Experts-Exchange in top bar (Search Scopes dropdown - right next to the EE Logo; User menus toggle button - Caret icon right next to the Search button; Or the User menu items also do toggle detailed blocks such as Notifications, Messages, etc.).
adra750Author Commented:
Okay, can you make an example
Duy PhamFreelance IT ConsultantCommented:
See an example here:

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