fixe hakimel#2217, add error helper message

HMarzban · Oct 24, 2018 · cb52851 · cb52851
1 parent c35cce5
commit cb52851
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/js/reveal.js b/js/reveal.js
@@ -553,6 +553,9 @@
 	 */
 	function setupDOM() {
 
+		if(dom.slides === null)
+			throw Error("RevealJs need a html element by class name of 'reveal' for initialize, like: <div class='reveal'></div>");
+
 		// Prevent transitions while we're loading
 		dom.slides.classList.add( 'no-transition' );