If you are not sure if the website you want to visit is safe, you can check it out here. Enter the address (url) of the website and see the invisible elements, such as a header or meta data.
site address:www.headfirstlabs.com/books/hfphp/hfphpmysql_ch07.pdf redirected to: www.safaribooksonline.com/library/view/head-first-php/978059615773...
site title:
Url ContentHyperText Markup Language (HTML)
MIME Type / Internet Media Typetext/html
MIME Type text
File Extension.html
More Details (link to:)Wikipedia: HTML
Powered by: Very Tiny URL Shortener at https://vturl.net VeryTinyURL

Header

HTTP/1.1 301 Moved Permanently
Date Mon, 23 Jul 2018 17:33:24 GMT
Server Apache
Location htt????/www.safaribooksonline.com/library/view/head-first-php/9780596157739/
Cache-Control max-age=2592000
Expires Wed, 22 Aug 2018 17:33:24 GMT
Content-Length 284
Content-Type text/html; charset=iso-8859-1

Load Info

load time (s)6.528873
redirect count1
speed download0
server IP151.101.121.132


* all occurrences of the string "http://" have been changed to "htt???/"