Make footer invisible on title slide

Change-Id: I2f7894cdde230027ccb7894d298695c35c8470b5
diff --git a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
index 4f68da0..853611a 100644
--- a/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
+++ b/inst/rmarkdown/templates/revealjs_presentation/resources/default.html
@@ -667,6 +667,35 @@
   })();
 </script>
 
+$if(theme-ids)$
+<script>
+    function makeFooterVisible() {
+      // document.querySelector("#ids-footer").style.opacity = 1;
+      document.querySelector("#ids-footer").style.display = null;
+    }
+
+    function makeFooterInvisible() {
+      // document.querySelector("#ids-footer").style.opacity = 0;
+      document.querySelector("#ids-footer").style.display = "none";
+    }
+
+    Reveal.on('ready', event => {
+      if (event.indexh === 0) {
+        makeFooterInvisible();
+      }
+    });
+    Reveal.addEventListener('slidechanged', (event) => {
+      if (event.indexh === 0) {
+        Reveal.configure({ slideNumber: null });
+        makeFooterInvisible();
+      }
+      if (event.indexh > 0) { 
+        Reveal.configure({ slideNumber: 'c' });
+        makeFooterVisible();
+      }
+    });
+</script>
+$endif$
 $for(include-after)$
 $include-after$
 $endfor$