Site shown in the video:- http://www.webtechball.wordpress.com/
In this examples you'll get to know how to create captcha code on your registration form. Hence the captcha code is not fixed that's why we use time intervals for creating captcha code because time is not stable and indeed it can't be repeated. The captcha code will change whenever you refresh your browser window.
On this page of the site you can watch the video online How to create captcha code in php with a duration of hours minute second in good quality, which was uploaded by the user mukul soni 18 February 2015, share the link with friends and acquaintances, this video has already been watched 11,312 times on youtube and it was liked by 25 viewers. Enjoy your viewing!