This is a great website! I use it every day to generate practice sheets. One improvement would be for the output page (in my case it's a PDF file) to not replace the current page, but to open on another tab in my browser.
Thanks again for producing this well-crafted website
If you use it every day, you can have a practice sheet emailed to you instead if you prefer. Check the "Send me a file regurlaly" checkbox.
About the new tab in the brower, I'll look at it but I don't know if it's feasable.
Check your browser and/or pdf plugin configuration. May be you can tweak them to open the file in another tab. Technically, the server just send a pdf file. It's up to the browser to act accordingly after that.
Another way to achieve that would be to show a link towards the pdf/html under the generator and let the user decide what to do with it. I am not enthousiast for that. because it adds another indirection level