Can't reload self-made captcha on the page using JS

Question

<a href="javascript:void(0);" onclick="document.getElementById("capchaimage").src="captcha.php"><img id="captchaimage" src="http://website.org/captcha.php" border="0" width="70" height="20" alt="Captcha image"></a>

Captcha image successfully loads but it's not possible to reload it with the code above. What am I doing wrong?

Thanks in advance.

score 1 · Answer 1 · answered Sep 25 '11 at 09:52

1

Your images are cached. Add a random string +(new Date).getTime() to at the query string after the image URL:

document.getElementById("capchaimage").src="captcha.php?"+ (new Date).getTime();

answered Sep 25 '11 at 09:52

Rob W

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`` Still doesn't work – Dmitry Ponkin Sep 25 '11 at 09:57
Replace the inner quotes by`"` or `'` (single-quotation mark). – Rob W Sep 25 '11 at 09:58
Thanks for priceless help, Rob! I owe you :) – Dmitry Ponkin Sep 25 '11 at 10:03

score 0 · Answer 2 · answered Sep 25 '11 at 09:51

You are replacing image src with exactly the same string.

You can try to work around that by using some "fake" arguments:

http://website.org/captcha.php?fake=234342412341

That way the browser will be forced to reload. The argument needs to be different each time of course (random, or just counter)

score 0 · Answer 3 · answered Sep 25 '11 at 11:01

Look carefully at your code:

<a href="javascript:void(0);" onclick="document.getElementById("capchaimage").src="captcha.php"><img id="captchaimage" src="http://website.org/captcha.php" border="0" width="70" height="20" alt="Captcha image"></a>
                                      ^                        ^

I'm surprised you are not getting JavaScript syntax errors. My advise is to move code to external functions to avoid the need of complex escaping.

Can't reload self-made captcha on the page using JS

3 Answers3