A read-more button the client sets with one tag

A German agency brought me a small animal-therapy practice whose training page made visitors scroll through every long text. The client wanted each text to open with a «Weiterlesen» (read more) button, and the page builder on the site had no simple option for it. I wrote a small script that finds WordPress’s standard more tag in the text, hides what follows inside the page-builder layout and adds a button in the theme’s own style that opens and closes it. Now the client places the more tag in her text, and the button appears by itself.