Storage [Q] What is Chromecast??? a detailed info plz :)

Can anybody tell my what is chromecast?
i heared that you plug it to TV and send the info over Wi-Fi from a Device such as android

At first, is it "Mirroring" or similar to DLNA?
i mean it's just for Photos and Videos and vice versa?

I Actually Want to Browse the Internet on My Tablet while viewing it on the TV
Or Precisely, i want to use My Galaxy Tab 3 7.0 as a Mini-PC and this Tab dosen't support USB OTG or HDMI/MHL Capabilities
so Using a Bluetooth Mouse and On-Screen Keyboard with streaming to TV Over Chromecast would be Everything i want
i just want to browse Facebook, nothing else.
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