TESTING A CODE

I've been asked by a colleague on how to create expandable post. After searching the internet, I came across this code that we can use in order to create that kind of expandable post. So, here I am, trying the code out on my current post. I hope that I'm lucky to get it right. Let me publish this post and see the result. Whether it works for me or not. Let's go!

my code testing was unsuccessful...