Add autofocus to input field

index.html

@@ -50,7 +50,7 @@
             </p>
         </details>
         <div class="box">
-            <input id="input" type="text" class="width:100%" autocomplete="off">
+            <input id="input" type="text" class="width:100%" autocomplete="off" autofocus>
             <br>
             <textarea id="output" class="width:100% mono-font" rows="8" style="resize: none" autocomplete="off" readonly>&lt;span lang=&quot;ja&quot;&gt;&lt;/span&gt;</textarea>
             <p><button id="copy" class="padding float:right">Copy</button></p>