Did you try it the way that Demo recommended?
Try it again in this order:
Close Safari completely from the app switcher window by double clicking the Home button and swiping up the Safari preview pane until it disappears from the screen. You may have to look for the Safari pane by scrawling to the left. Then go to Settings > Safari > Clear History and Website Data. Then do a forced restart. Hold down the Home and Wake/Sleep buttons at the same time for about 15-20 seconds until the Apple logo appears.
If that does not help, try turning off Safari Suggestions. Settings > Safari > Safari Suggestions to Off (not green). Also consider deleting the Facebook App and reinstalling it.
If that does not help you may have to do a system restore following the instructions below.
First backup your device using iTunes. Then import your photos to your computer and copy all important data. Try restoring from backup first and testing it. If it does not help, you may have to restore as New and reconfigure from scratch as the backup could be corrupted. For this reason it is important to have your photos and data saved separately from the backup.
https://support.apple.com/en-us/HT201252