Add undo/redo all buttons for fast history traversal

takhta.html

@@ -211,11 +211,19 @@
 					<input type="button" value="Redo" onclick="redoMove()">
 					<input type="button" value="Flip board" onclick="flipBoard()">
 				</form>
-				<p><form id="shipping">
+			</p>
+			<p>
+				<form id="rewind">
+					<input type="button" value="Undo all" onclick="undoAll()">
+					<input type="button" value="Redo all" onclick="redoAll()">
+				</form>
+			</p>
+			<p>
+				<form id="shipping">
 					<input type="button" value="Download moves" onclick="download()">
 					<input type="file" id="moveupload" name="moveupload">
 					<button type="button"><label for="moveupload">Upload moves</label></button>
-				</form></p>
+				</form>
 			</p>
 			<p>
 				<form id="options">
@@ -650,6 +658,20 @@
 				return true;
 			}
 
+			function undoAll() {
+				while (moveHistory.length > 0) {
+					undoMove();
+				}
+			}
+
+			function redoAll() {
+				while (moveFuture.length > 0) {
+					if (!redoMove()) {
+						break;
+					}
+				}
+			}
+
 			function flipBoard() {
 				let oldBoard = document.getElementById('board').firstElementChild;