update js

assets/js/script.js

@@ -1,6 +1,6 @@
 function move(event) {
     var k = event.keyCode,
-        chrId = document.querySelector('.block'),
+        chrId = document.querySelector('#block1'),
         chr = {
             updown: function () {
                 var y = parseInt(getComputedStyle(chrId).top);

index.html

@@ -10,7 +10,7 @@
     <h1>de_tank</h1>
 </section>
 <section class="map">
-    <div class="block"></div>
+    <div id="block1" class="block"></div>
 </section>
 </body>
 <script src="assets/js/script.js"></script>