JS - Element properties

element.previousSibling or node.previousSibling: returns the previous sibling of the node; "null" if no previous sibling exists.

Coffee (first item)
Tea (second item)

The HTML content of the previous sibling of the second list item is:

Note: Whitespace between elements is considered text nodes. If you add whitespace between the two li elements, the result will be "undefined".

code:

                <div>
                    <ul><li id="item1">Coffee (first item)</li><li id="item2">Tea (second item)</li></ul>
                    <p>The HTML content of the previous sibling of the second list item is: <span id="prop"></span></p>
                    <p style="font-size: 0.9vw;"><strong>Note:</strong> Whitespace between elements is 
                    considered text nodes. If you add whitespace between the two li elements, the result will be "undefined".</p>
                </div>
                <script>
                    let text = document.getElementById("item2").previousSibling.innerHTML; 
                    document.getElementById("prop").innerHTML = text;
                </script>

JS - element properties - previousSibling

returns the previous node at the same node tree level.