JSFiddle - React, Tailwind, and code Playground

HTML

<div class="widget_box">
    <div class="widget_box_content">
        <a href="#" class="widget_minimize">link</a>
        <div class="widget_box_content_cont">
            some content
        </div>
    </div>
    <div class="widget_box_content">
        <a href="#" class="widget_minimize">link 2</a>
        <div class="widget_box_content_cont">
            some content 2
        </div>
    </div>    
</div>

JavaScript

var min = $(document.body).getElements('a.widget_minimize');

// store an instance into each content div and set initial state to hidden.
$$("div.widget_box_content_cont").each(function(el) {
    el.store("fxslide", new Fx.Slide(el).hide());
});

min.addEvent('click', function(event) {
    event.stop();
    this.getParent().getElement(".widget_box_content_cont").retrieve("fxslide").toggle();
});