I know there are many reason why you need to know that how to block a websites. Some common reasons are you have been targeted by spammers who use adware and popup to attack your system. And other reasons may be prevent your friends or relative from having access to certain site content such as social networking site’s like Facebook, Twitter or porn site.
Anyway there are many tools for blocking website’s in chrome you can easily find it by using this link.
But in this all extension's my favorite is NANNY. To install it click on link you will see Google Chrome web store with some extension .Find Nanny for Google chrome and click to “ADD TO CHROME” button as shown in screenshot(for zoom click on image)
When you click on ADD TO CHROME button a popup window will appears click to install.(for zoom click on image)
With in a few second Google nanny will be installed and its icon will be display in right top ,Right click on it and go to option .
Then new tab will be open on your browser hear you add site name (eg. Facebook…) or site url (xyz.com) and block time(eg. 0900-1700,1900-2100 to block during 9AM-5PM and 7PM-9PM) and max time(eg. 60 min) and then save url as shown in screenshot.
(for zoom click on image)
Last but most important step is go to LockDown select site name at CONFIGURE LOCKDOWN put Duration (eg. 24 hours and 55 minute) and click on Begin LockDown .
That’s it you have don’it and to remove blocking on websites just go to edit in Blocked URLs but its work after blockset is over but no need to wary for any problem just uninstall and re-install it