How to create simple javascript/jquery client side captcha? How it may be realize, thx.
A:
What is the point of a client-side CAPTCHA?!?
The whole purpose of CAPTCHA is to prevent the server from responding to requests that are made by non-humans. What are you trying to achieve?
Spam-bots will not be executing your JavaScript. Humans will. Spam-bots will not get annoyed (even if they could). Humans can, and will.
Amadan
2010-07-07 15:38:07
A:
Client-Side captchas do not provide the protection a server-generated captcha would because the server can not check if the solved captcha is solved correctly.
chiborg
2010-07-07 15:39:20
A:
That is not possible.
You could create something that looks like a CAPTCHA, but it would only run when it's not needed, i.e. when the page is shown in a browser. When it's needed it won't run, as the program trying to break in won't run the client side script.
Guffa
2010-07-07 15:47:09
"That is not possible." - such a strong phrase, what proves itself wrong time after time
Fabiano PS
2010-07-07 18:56:26
@Fabiano: Such a strong phrases are waranted in cases like this. A client side CAPTCHA would actually be worse than nothing at all, as it gives a false sense of security, but offers no real security what so ever.
Guffa
2010-07-07 21:37:09
I see your point and agree on your comment. But about *being not possible* likely, isn't right
Fabiano PS
2010-07-09 18:15:10
@Fabiano: If you want something that *looks* like a CAPTCHA, it's of course possible to do using client script, but to make one that actually works is not possible.
Guffa
2010-07-10 13:52:56
A:
if your purpose is to simply deflect most bots, you might be able to get away with a simple script that chooses 2 numbers at random and asks user to add them.
Scott Evernden
2010-07-07 15:47:21
Ок, but if spam bot use form.Submit() it's validation is not saffely,how i may check condition before form.Submit()If atribut on submit hadles only when member click on button submit
Tamifist
2010-07-07 15:52:46
That's exactly what everyone keeps telling you - it is not possible. you can't catch `form.submit()`. And especially you can't catch someone who parses your web-page, constructs a POST request and contacts your server programmatically (without a browser, without JavaScript).
Amadan
2010-07-10 15:23:23
+3
A:
Why don't you use reCAPTCHA ? It's free, very efficient, and provides accessibility functionnalities.
I hope I could be of any use. Regards from France ;)
Squ36
2010-07-07 15:54:53
A:
here you are ;)
<html>
<head>
<title>TestPage</title>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<script type="text/javascript">
var captchaText;
$(function() {
var pre = $('#captcha');
captchaText = pre.text();
pre.text('');
var lines = ['', '', '', '', '']
for (var ixLetter = 0; ixLetter < captchaText.length; ixLetter++)
{
var letter = captchaText.substr(ixLetter, 1);
var letterLines = letters[letter];
for (var ix = 0; ix < 5; ix++)
{
lines[ix] = lines[ix] + ' ' + letterLines[ix];
}
}
for (var ix = 0; ix < 5; ix++)
{
pre.append(lines[ix] + '\n');
}
});
function check()
{
if ($('#captchaCheck').val() == captchaText)
{
alert('you are probably human');
}
else
{
alert('you probably made a mistake. Don\'t worry. To err is also human.');
}
}
var letters = {
h: [
'HH HH',
'HH HH',
'HHHHHH',
'HH HH',
'HH HH'
],
i: [
'II',
'II',
'II',
'II',
'II'
]
// etc
}
</script>
</head>
<body>
<pre id="captcha">hi</pre>
Please type what you see: <input id="captchaCheck"/> <input type="button" value="Check" onclick="check()"/>
</body>
</html>
Jan Willem B
2010-07-07 16:02:16
This is fun but if you use the real letters to represent the letters what is the point? :P Also consider that he is doing this to avoid bots so the submit button and href of the form should be written on a succesful captcha
Fabiano PS
2010-07-07 18:54:25