Browsers (IE and Firefox) freeze when copying large amount of text
- by Matt
I have a web application - a Java servlet - that delivers data to users in the form of a text printout in a browser (text marked up with HTML in order to display in the browser as we want it to). The text does display in different colors, though most of it is black. One typical mode of operation is this:
1. User submits a form to request data.
2. Servlet delivers HTML file to browser.
3. User does CTRL+A to select all the text.
4. User does CTRL+C to copy all the text.
5. User goes to a text editor and does CTRL+V to paste the text.
In the testing where I'm having this problem, step #2 successfully loads all the data - we wait for that to complete. We can scroll down to the end of what the browser loaded and see the end of the data. However, the browser freezes on step #3 (Firefox) or on step #4 (IE). Because step #2 finishes, I think it is a browser/memory issue, and not an issue with the web application.
If I run queries to deliver smaller amounts of data (but after several queries we get the same data we would have above in one query) and copy/paste this text, the file I save it into ends up being about 8 MB. If I save the browser's displayed HTML to a file on my computer via File-Save As from the browser menu, it works fine and the file is about 22 MB.
We've tried this on 2 different computers at work (both running Windows XP, with at least 2 GB of RAM and many GB of free disk space), using Firefox and IE. We also tried it on a home computer from a home network outside of work (thinking it might be our IT security software causing the problem), running Windows 7 using IE, and still had the problem. When I've done this, I can see whatever browser I'm using utilizing the CPU at 50%. Firefox's memory usage grows to about 1 GB; IE's stays in the several hundred MBs. We once let this run for half an hour, and it did not complete.
I'm most likely going to modify the web app to have an option of delivering a plain text file for download, and I imagine that will get the users what they need. But for the mean time, and because I'm curious - and I don't like my application freezing people's browsers, does anyone have any ideas about the browser freezing? I understand that sometimes you just reach your memory limit, but 22 MB sounds to me like an amount I should be able to copy to the clipboard.
