By Molly Morris, memDesigns, August 2008
© Molly Morris, All rights reserved
Why is a robot interested in filling out your form?
In general, web robots are visiting sites to hack, spam and collect email addresses. Unless your site has high-level intelligence secrets, you’re probably not too worried about hackers. But spammers are concerning for a few reasons. First of all, they fill your Inbox with unwanted junk. Secondly, those emails may carry viruses. Thirdly, if your submission is answered by an automatically generated email from you, then every time you get a form submission, you send your email address to the party submitting the form. If that party meant harm, or is a spammer, and you’ve just handed over your email address, you’ve made them very happy.
You can prevent robots from submitting your form
When you submit a form over the Internet and you are asked to type out the word you see in a box – usually somewhat obscured by some optical illusion effect – or answer a skill-testing question, you are using a CAPTCHA. I’m embarrassed to admit that, up until recently, I thought CAPTCHA was some slangy (think Chicago Mafia) way of referring to “capturing” information. In fact, CAPTCHA is an acronym for Completely Automated Public Turing Test to tell Computers and Humans Apart. A Turing Test is an experiment described by Alan Turing in the 1950s to test whether computers could have intelligence. It goes like this: A human judge engages in a natural language conversation with two other parties, one of which is a human and the other a machine; if the judge cannot tell which is which, then the machine is said to pass the test.
Including a CAPTCHA on a web form prevents machines, in this case web robots, from submitting the form. As it turns out, computers do not have intelligence, and only a human can reliably complete a CAPTCHA field. When the CAPTCHA field is not completed, or completed incorrectly, the form is rejected, you don’t get an email, and all is well.
It’s comforting to know we humans can still beat computers.