there are a few ways of doing this, a few different ways of doing each.
One way is to use some validation on the form. You could validate the form through the HTML, Spry do some nice validation widgets you can use. These basically check the the fields are what they are intended to be. For instance, you can make an input field an email address, and set the page to insist on having an email address typed in it, then the form will vaildate it only if the text has an @ and a . in it.... something@somewhere.showwhere
Of course, this will not stop people typing in nonsence email addresses, but it can help keep away some auto spammers.
You can set other fields, such as name, to have a minimum value or something like that...
This method tends to rely on javascripting, and of course, javascripting can be disabled, thus the validations will not matter and you can still be spammed.
You could also validate the form through the PHP... this works in much the same way, but as it is in the PHP form it tends to fend off a bit more spam... you can google PHP form validation and see lots of examples...
The more commonly used thing now is the CAPTCHA. This is the name for those image based distorted text charachters or words that you have to type into a box to validate... you know... the ones sometimes you cant read too clearly... Basically things that can be understood by humans, but no current computer prgrams can understand them.
again, goolge free CAPTCHA and you will find plenty you can use on your site.
http://www.captcha.net/ for instance.
Richard Williams
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