A CAPTCHA (known as "Completely Automated Public Turing test to tell Computers and Humans Apart") is a kind of challenge-response test that is used in computing to find out whether or not the user is human. An ordinary kind of CAPTCHA requires that the user key in the letters of a fuzzy image, sometimes with the supplement of a masked series of letters or digits that emerge on the screen.
CAPTCHA can not only create these tests automatically but also store them. The basic principle is that they admit all humans and discard almost all machines since humans can usually read tarnished images, but OCR machines cannot.For more details please visit http://www.protectwebform.com/.
While business websites wish to attract maximum traffic they are wary of spammers misusing your personal information. Therefore, they provide a feature on their site to get response from visitors and avoid spam. Since posting an email on your website is a sure shot invitation for spammers, they use a whole lot of tricks and methods to conceal your email address so that spammers can’t find it.
One way to do it is by embedding Java script in the web page to capture the email address when the page is displayed to the visitor. An enhanced alternative is to use CAPTCHA along with the website forms. You must have seen this feature in use on big websites which require you to sign up.
The person registering with these sites is required to identify and enter some indistinct characters shown on the screen for confirmation before submitting the form. The logic here is that computer generated programs will not be able to identify these unclear characters and alphabets. The form is therefore construed as automatically authenticated and submitted by a human visitor rather than some computer generated program.
The greatest advantage of CAPTCHA is that it averts bots from misusing Internet services.Bots are programs that model as humans on the Internet. They are created not to rule but to sell, sign up for numerous free email accounts every moment, sending millions of Spam messages from them. They get into chat rooms; they accumulate personal information; and they post links to promotional sites. They create worms, break password systems, assault confidentiality, and deplete resources. If you want to avoid all these dangers you can customize your CAPTCHA with colors and fonts of your choice. You can also choose the image you like, with CAPTCHA Plugin. For furher details visit http://www.protectwebform.com/plugin_wordpress.
A technique of improving the CAPTCHA to make work easier was proposed by ProtectWebForm and was called "Smart CAPTCHA". [See http://www.protectwebform.com/smartcaptcha]. Developers recommend joining the CAPTCHA with JavaScript support. Since it is very difficult for most spam robots to carry out scripts, using an easy script, which fill up the CAPTCHA fields and conceal the image and the field from human eyes was planned. The "Smart CAPTCHA” is a case of safety through shadows. They defend your site because authors do not come across the exact kind of JavaScript in question.
Inserting CAPTCHA code in your web pages provides a dependable method to authenticate that the registration is being tendered by a human being and not by some computer generated process. The use of CAPTCHA is therefore becoming increasingly popular.
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