Hi...! Every one let us see about the most credential aspect "CAPTCHA". This is the one you find during the user side verifiction code and you will be typing the text in an enumerated like form on a specified section.
Okay, we will discuss about types of CAPTCHA and its necessity below
Whereas Modern CAPTCHA’s include following types,
• Animated CAPTCHAs
• 3D CAPTCHA
• ASCII art
• Reverse CAPTCHA
CAPTCHA is quite commonly necessary to stop BOT’s intrusion moreover computer access to the human prior sites. As per security analysis it is must because as said previously to stop the BOT’s intrusion on some high defined logical reasoning access which would take more time for an unauthorized user the BOT’s makes them easier.