captcha refreshing with refresh button

I am developing a website with php, i'm also using javascript in it开发者_开发技巧.

I have to refresh captcha in my website with a refresh button when a captcha is unreadable to a user.

how can i do this. please share any idea or codes to me

Thanks

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Why are you hand-rolling this out yourself? Did you try Recaptcha? http://recaptcha.net/whyrecaptcha.html

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You can use the ReCaptcha .

Otherwise it depends on the way you have implemented it .. Ajax seems like the way to go ..

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Yes, the ReCaptcha is the perfect, and safe solution to go for, just register there and implement that on your site, it should not be that difficult :)

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Given that you have an implementation of Captcha on your website. An approach suitable for your needs is an Ajax request. Ajax (XMLHTTPRequest) Tutorial

If you do not want to hard-code everything and have the work already done for you, look at reCAPTCHA or any other Captcha providing company. Although, not entirely sure if they offer a non-refreshing captcha page.

I have no experience in using it, besides when editing posts too many times, StackOverflow will redirect me to the "Human Verification" page.