Use placeholder attribute for Comment message

- Remove global aStr.comment
- Remove global window.commentEmptyText
- Remove head.tpl $comment parameter

view/theme/quattro/templates/comment_item.tpl

@@ -37,11 +37,12 @@
 					<li><a class="editicon videobb shadow"
 						style="cursor: pointer;" title="{{$edvideo}}"
 						data-role="insert-formatting" data-comment="{{$comment}}" data-bbcode="video" data-id="{{$id}}"></a></li>
-				</ul>	
-				<textarea id="comment-edit-text-{{$id}}" 
-					class="comment-edit-text-empty" 
-					name="body" 
-					onFocus="commentOpen(this,{{$id}}) && cmtBbOpen({{$id}});" >{{$comment}}</textarea>
+				</ul>
+				<textarea id="comment-edit-text-{{$id}}"
+					class="comment-edit-text-empty"
+					name="body"
+					placeholder="{{$comment}}"
+					onFocus="commentOpen(this,{{$id}}) && cmtBbOpen({{$id}});"></textarea>
 				{{if $qcomment}}
 					<select id="qcomment-select-{{$id}}" name="qcomment-{{$id}}" class="qcomment" onchange="qCommentInsert(this,{{$id}});">
 					<option value=""></option>