Add smart poster and external type records examples

Signed-off-by: Zoltan Kis <zoltan.kis@intel.com>

index.html

@@ -871,7 +871,7 @@ <h4>
     </p>
     <p>
       For external type records, local types are application specific.
-      Local types are exposed as a recordType, prefixed with "`-`".
+      Local types are exposed as a recordType, in this example prefixed with "`-`".
     </p>
     <p>
       This example shows how to read an external record for social posts,
@@ -919,6 +919,93 @@ <h4>
   reader.scan({ recordType: "example.com:sp"});
       </pre>
     </aside>
+    <aside title="Push a smart poster message" class="example">
+      <p>
+        Smart poster defined in NFC Forum Smart Poster Record Type Definition
+        specification. It is an NDEF record that contains an <a>NDEF message</a>
+        as payload, which in turn may contain several records: a URI record that
+        refers to a content, and additional optional records for that content's
+        title, icon, size, type and possible action (e.g. send SMS, make call,
+        launch browser, or save for later, or open for editing, etc).
+      </p>
+      <pre class="highlight">
+        const writer = new NFCWriter();
+        let sp = new NDEFMessage({
+          records: [
+            {
+              recordType: "url",
+              data: "https://my.org/content/19911"
+            },
+            {
+              recordType: "t", // type, a local type to Sp
+              data: "image/gif"
+            },
+            {
+              recordType: "text",
+              data: "Funny dance"
+            },
+            {
+              recordType: "s",  // size, a local type to Sp
+              data: 4096  // byte size of the content at the URL above
+            },
+            {
+              recordType: "act",  // action, a local type to Sp
+              data: 0  // do the action, in this case open in the browser
+            },
+          ];
+        });
+        writer.push({ records: [
+          {
+            recordType: "smart-poster",
+            data: sp.records
+          }
+        ]}).catch(_ => {
+          console.log("Push failed");
+        });
+      </pre>
+    </aside>
+    <aside title="Push an external record with an NDEF message as payload"
+           class="example">
+      <p>
+        External type records can be used to create application defined records
+        that may even contain an <a>NDEF message</a> as payload.
+      </p>
+      <p>
+        This example show how to do the previous Smart Poster use case with
+        external records. In this case, content sourcing and the action
+        mechanism are internal to the application.
+      </p>
+      <pre class="highlight">
+        const writer = new NFCWriter();
+        let ext = new NDEFMessage({
+          records: [
+            {
+              recordType: "url",
+              data: "https://my.org/game/19911"
+            },
+            {
+              recordType: "text",
+              data: "Game context given here"
+            },
+            {
+              recordType: "opaque",
+              mediaType: "image/png"
+              data: getImageBytes(fromURL);
+            }
+          ];
+        });
+        writer.push({ records: [
+          {
+            recordType: "external",
+            data: ext.records  // embedded message
+          }
+        ]}).catch(_ => {
+          console.log("Push failed");
+        });
+      </pre>
+    </aside>
+
+
   </section> <!-- Usage examples -->
 
   <section class="informative"> <h3>Use Cases</h3>