lj-cut. It allows to show only a part of the post on the main page, and reveal the rest on a separate page. I was looking for a similar feature on blogger, as my posts with code examples are quite lengthy.
Don't need to say much more, the solution is here. Don't forget the step 1, I started from the red part and scratched the head what's wrong. P.S. I ended up changing their tags from span to div, as span can not include
<pre>elements among many other limitations.