How can I check a checkbox when another checkbox is checked? [JavaScript]

So I have a little form which you can see at the bottom. And I want to know how I can make a JavaScript function where if I, for example, check checkbox 3 it will also check checkboxes 2 and 1. I have been on the internet looking for hours now and most stuff either doesn't wanna work or involves jQuery. I'd rather use HTML/JavaScript only.

I thank you for taking your time to at least read this!

<h3>HTML</h3>
    <label><input type="checkbox" name="html1" value="html1" id="html1"/><span class="label-text"></span></label>
    <label><input type="checkbox" name="html2" value="html2" id="html2"/><span class="label-text"></span></label>
    <label><input type="checkbox" name="html3" value="html3" id="html3"/><span class="label-text"></span></label>
    <label><input type="checkbox" name="html4" value="html4" id="html4"/><span class="label-text"></span></label>
    <label><input type="checkbox" name="html5" value="html5" id="html5"/><span class="label-text"></span></label>