I want javascript for Image captcha in html code.
Whcih generates images dynamically and match the given character with image characters. Before entering into the new page it should have to check whether both are same or not
I want to create it in my own, How i can achieve it?

Thanks in Advance,
Praveen J

I want javascript for Image captcha in html code.
Whcih generates images dynamically and match the given character with image characters. Before entering into the new page it should have to check whether both are same or not
I want to create it in my own, How i can achieve it?

Thanks in Advance,
Praveen J

• javascript
• html

Share Improve this question Follow edited Mar 12, 2009 at 6:18 praveenjayapal asked Mar 12, 2009 at 6:07 praveenjayapalpraveenjayapal 38.6k3131 gold badges7474 silver badges7474 bronze badges 2

• do you want to do the distortion yourself too? – markus Commented Mar 12, 2009 at 6:35
• yes, i want to create a captcha by own – praveenjayapal Commented Mar 12, 2009 at 7:10

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2 Answers 2

Sorted by: Reset to default 4

Use recaptcha. It's what stackoverflow uses!

I want javascript for Image captcha in html code. Whcih generates images dynamically and match the given character with image characters. Before entering into the new page it should have to check whether both are same

Whilst you could conceivably write some shapes to a <canvas>, SVG or VML element — or even (on non-IE browsers) create an image with a ‘data:’ URL created from pixel values —  there is no point.

Any wholly client-side approach to captcha is already promised because it needs to know the ‘right’ answer to check against. An attacker can just run the JavaScript themselves to find out the answer. Or just turn JavaScript off to avoid the checks.

To do captchas you need server-side scripting, which the attacker does not have access to, to do the work.