site/_includes/scripts/alt-popup.js

// custom popups that appear on hover that uses the alt/aria-label attribute on elements
// replacement for using title without the issue it causes with screen readers and such
document.addEventListener("DOMContentLoaded", function () {
    let popup = document.getElementById("alt-popup");

    // add popup to all elements with alt or aria-label
    function initializePopups() {
        // find all elements with alt or aria-label
        const elementsWithAlt = document.querySelectorAll("[alt], [aria-label]");

        // add mouse events to each element
        elementsWithAlt.forEach((element) => {
            element.addEventListener("mousemove", showPopup);
            element.addEventListener("mouseout", hidePopup);
        });
    }

    // show popup and position it near the cursor
    function showPopup(event) {
        // get alt text or aria-label
        const altText = event.target.getAttribute("alt");
        const ariaLabel = event.target.getAttribute("aria-label");
        
        // Use alt text if available, otherwise use aria-label
        const displayText = altText || ariaLabel;

        if (displayText) {
            // use text in popup
            popup.textContent = displayText;
            
            // Make the popup visible but with position:fixed and visibility:hidden
            // so we can measure its dimensions without it being visible yet
            popup.style.opacity = "0";
            popup.style.visibility = "visible";
            popup.style.position = "fixed"; // Changed from absolute to fixed
            
            // Get viewport dimensions
            const viewportWidth = window.innerWidth;
            const viewportHeight = window.innerHeight;
            
            // Get popup dimensions
            const popupWidth = popup.offsetWidth;
            const popupHeight = popup.offsetHeight;
            
            // Use clientX/clientY which are relative to the viewport (for fixed positioning)
            let leftPos = event.clientX + 20;
            let topPos = event.clientY + 20;
            
            // Check if popup would extend beyond right edge of viewport
            if (leftPos + popupWidth > viewportWidth) {
                // Flip to left side of cursor
                leftPos = event.clientX - popupWidth - 10;
            }
            
            // Check if popup would extend beyond bottom edge of viewport
            if (topPos + popupHeight > viewportHeight) {
                // Flip to above cursor
                topPos = event.clientY - popupHeight - 10;
            }
            
            // Additional check if flipping to left puts it offscreen
            if (leftPos < 0) {
                leftPos = 10;
            }
            
            // Additional check if flipping to top puts it offscreen
            if (topPos < 0) {
                topPos = 10;
            }
            
            // Set the final position and make it visible
            popup.style.left = leftPos + "px";
            popup.style.top = topPos + "px";
            popup.style.opacity = "1";
            popup.style.visibility = "visible";
        }
    }

    function hidePopup() {
        popup.style.opacity = "0";
        popup.style.visibility = "hidden";
    }

    initializePopups();

    if (window.MutationObserver) {
        const observer = new MutationObserver((mutations) => {
            mutations.forEach((mutation) => {
                if (mutation.addedNodes.length) {
                    initializePopups();
                }
            });
        });

        // Only set up the observer once
        if (document.body) {
            observer.observe(document.body, { childList: true, subtree: true });
        }
    }
});