I'm designing a portal of sorts that allows users to create accounts for future activity on my site. In any event, I like the "random security image" some sites have been using to prevent bots from signing up random accounts on the server.
Since I am somewhat of a perfectionist, I like to include error checking based on credentials. For example, if the username already exists, error...if all information required wasn't inputted, error...and if the random security results don't match what the user puts in, error.
Well, when the error page gets generated, it cache's the image in the users browser, yet the code generates new data. If one were to reload the browser while on this error page, the image changes accordingly.
I've tried both the pragma tag and the Expires=-1 tag, but neither work well enough.
Is there a way I can get around caching?
