Dont store empty classes or events if they are null upon change.

src/sheet.js

@@ -12,7 +12,8 @@ class Sheet extends IgniteElement {
             items: ["1", "2"],
             href: "www.google.com",
             name: "default content",
-            linkClick: this.onClick
+            linkClick: this.onClick1,
+            linkClick2: this.onClick2
         };
     }
 
@@ -29,15 +30,17 @@ class Sheet extends IgniteElement {
                     new html("<h3>---- begin sheet's slot ----<h3>"),
                     new slot(this),
                     new html("<h3>---- end of slot ----</h3>"),
-                    new a("I go nowhere, but you can click me ;)").on("click", this.linkClick)
+                    new a("I go nowhere, but you can click me ;)").on("click", this.linkClick).on("click", this.linkClick2)
                 )
             );
     }
 
-    onClick(event) {
-        console.log("Element was clicked!");
-        console.log("Event:");
-        console.log(event);
+    onClick1(event) {
+        console.log("Element was clicked 1!");
+    }
+
+    onClick2(event) {
+        console.log("Element was clicked 2!");
     }
 }