I have the following to pull out just Jan in "January"
At first, I thought you were printing Janu.
You've requested to extract a substring starting at index 0 through 3. If you count from zero to three, you will end up with four characters. J is 0, a is 1, n is 2, and u is 3. However, according to specifications listed on Mozilla Developer's Network, the ending range is not included, so it would only print index 0 through 2.
After seeing pbawler's response, I decided to run both your code and pbawler's... and the below does print out "Jan". I also do not receive any errors from the console or Codecademy.
Do you mind sharing your complete code as it is listed on the script.js window, as well as the output of the Console?