vanilla-click-handler.js

;(function(handlers) {
	if (!handlers) {
		throw new Error('Nothing to handle');
	}

	document.documentElement.addEventListener('click', function(event) {
		var handler = event.originalTarget.getAttribute('data-handler');
		if (!handler) {
			// nothing to do
			return;
		}
		if (event.originalTarget.tagName === 'A' && (event.metaKey || event.ctrlKey || event.shiftKey)) {
			// honour default behaviour on <a>s when using modifier keys when clicking
			// meta / ctrl open in new tab
			// shift opens in a new window
			return;
		}
		if (typeof handlers[handler] === 'function') {
			handlers[handler].call(event.originalTarget, event);
		}
		else {
			if (console && console.log) {
				console.log('unknown handler \'%\'s on %o', handler, event.originalTarget);
			}
		}
	});

}({
	'example-handler': function(event) {
		event.preventDefault();
		// I'm the example handler
	}
}));