Add th3.htm demo to api.htm

Author: linev

docs/api.htm

@@ -4,7 +4,7 @@
       <!-- As template three.js web site was used -->
       <meta charset="UTF-8">
       <title>JavaScript ROOT API examples</title>
-      <link rel="shortcut icon" href="img/RootIcon.ico">
+      <link rel="shortcut icon" href="./img/RootIcon.ico">
       <meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
       <script type="text/javascript" src="scripts/JSRoot.core.js"></script>
       <meta property="og:title" content="JSROOT API examples"/>
@@ -177,8 +177,9 @@ <h1 id="version"><a href=".." style="color:green">JSROOT</a></h1>
               { name: "With require.js", url: "demo/use_requirejs.htm", title: "Load JSROOT libraries with require.js", src: true },
               { name: "UI with require.js", url: "indexr.htm?file=" + filepath + "danilo5.root&item=canvas;1", title: "Load and use default JSROOT UI with require.js" },
               { name: "UI with SAP loader", url: "indexsap.htm?file=" + filepath + "danilo5.root&item=canvas;1", title: "Load and use default JSROOT UI with SAP OpenUi5 loader" },
-              { name: "TH2", url: "demo/th2.htm", title: "Produce and draw ROOT histogram in JavaScript", src: true },
-              { name: "TH2 req", url: "demo/th2_requirejs.htm", title: "Produce and draw ROOT histogram in JavaScript (use require.js)", src: true },
+              { name: "TH2", url: "demo/th2.htm", title: "Produce and draw ROOT TH2 histogram in JavaScript", src: true },
+              { name: "TH2 req", url: "demo/th2_requirejs.htm", title: "Produce and draw ROOT TH2 histogram in JavaScript (use require.js)", src: true },
+              { name: "TH3", url: "demo/th3.htm", title: "Produce and draw ROOT TH3 histogram in JavaScript", src: true },
               { name: "TF1 req", url: "demo/tf1_requirejs.htm", title: "Load ROOT canvas with TF1, use require.js for scripts loading", src: true },
               { name: "THStack", url: "demo/thstack.htm", title: "Produce and draw THStack", src: true },
               { name: "TMultiGraph", url: "demo/multigraph.htm", title: "Produce and update TMultiGraph in JavaScript", src: true },