While I was doing laundry, my friends and I decided to mess around on TypeRacer, a popular web game where you race against others in a typing test to see who can type a phrase or sentence the fastest. Normally, I have an average typing speed of 120~130 wpm (words per minute), but just for fun, I wanted to mess with my friends. In this techsploration, I’m going to explain how I did it.
Let’s go into a practice game and snoop around to see what we can find.
Here’s what the interface of a practice game looks like. Let’s open our good friend, the Chrome Inspector tool.
I checked to see if jQuery was available to me, which it was. This is very handy for manipulating and accessing data on the site.
Hmm, this <span> contains all the words except the first one. What’s special about the first word?
It seems like the word you’re currently on is contained in a different <span> tag with another unique ID. Not a problem, since I can select it and get its text as well.
I did a little more testing and refreshed the page a few times. It seems that the uid of the span changes, but usually is a number less than 100. We can just try out every number then. I threw together a quick script to output the race text.
The computation time for just guessing the uid is pretty trivial, so this script worked fine.
After some further inspection, I realized that instead of guessing the uid, I could select the text’s container element, which doesn’t have a uid and stays the same.
Now all I have to do is run this script, paste the text into it, and then put my mouse cursor on the input box and the script will take care of the rest. The two second window before it starts typing allows me to switch back to TypeRacer and select the input box. I used an interval of 0.05 seconds between typing each character so that the typing would seem somewhat human.
Here’s what that looks like:
Of course, you can see at the end of this video that it triggers a typing challenge test. This one is much harder since it features a captcha style typing challenge, which you need to beat with a similar wpm in order for your score to be considered valid.
I tried playing around with the typing interval to see what other things the site would do. As long as I kept the bot’s wpm below 100, I never had to do the captcha test. If I set the typing interval to zero, I could achieve a wpm of more than 300, but the website would automatically flag and disqualify it.
An interesting thing is that TypeRacer calculates your wpm as words entered divided by total time elapsed, which means that having my bot type the words slowly over 10 seconds is the same as having it enter all the words instantly after waiting 10 seconds.
This was a pretty fun way to pass the time while I was waiting for my dryer cycle to finish. If I revisit this in the future, I might write a part 2 where I use OCR or opencv to beat the captcha test as well. I have to go fold my clothes, so that’s all I have for now. Thanks for reading!
Follow me on Twitter: @omgimanerd
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