base-modal.js

// Listen for all clicks on the document
document.addEventListener('click', function (event) {

	// event.target is the clicked element
	// If the link has the data-modal selector, we'll use it to toggle our modal
	// Make sure to include a polyfill for matches(): https://vanillajstoolkit.com/polyfills/matches/ 
	if (event.target.matches('[data-modal]')) {

		// We can embed the message directly in the modal link if you want using the data-modal attribute
		// Your link would look like this:
		// <a data-modal="We want to display this message in the modal. Woohoo!" href="#">Click Me</a>
		var message = event.target.getAttribute('data-modal');

		// Get your modal
		var modal = document.querySelector('#some-modal');
		if (!modal) return;

		// Set the modal message
		modal.innerHTML = message;

		// Then run whatever code you use to open the modal...
		
	}

}, false);