javascript - Defeating spam registrations -

i trying learn as possible running high-profile website. designing user registration screens , thinking typical captcha, or annoying alternatives. in opinion, having them either causes accessibility issues, or bothers potential customers , inhibits registration process.

my question whether spambots recognize , trigger javascript events, such keydown or keypress event on input field. can gather, bots form posts via action attribute , don't programmatically "fill out" web forms.

in theory, add javascript following:

<input name="email" /> <input name="human" type="hidden" /> <script> var emailfield = document.getelementbyid( 'email' ); emailfield.onkeydown = function( ) {    document.getelementbyid( 'human' ).value = "human"; }; </script> 

then, on server side, verify post data includes value of "human" hidden form field.

is viable solution, @ least effective typing in bunch of random, difficult-to-read characters? using random generated value server more helpful in repetitive attempts static value of "human"?

most spam bots <form> on page , post data directly url specified in action attribute. simple, lightweight, , easy do.

some spam bots use headless browser (such phantomjs) executes javascript on page. these spam bots harder fool, few bots use method since more expensive (in cpu , ram).

i've found it's fine go blocking common spam bots through honeypot (field on page removed programmatically, , other similar methods). bots through, , manual analysis find way exploit page still in. sites, enough, , provides balance in preventing spam while keeping site usable.