解决按钮点击后虚线框不消失的问题

src/main/webapp/WEB-INF/views/preview2.html

@@ -17,24 +17,19 @@
 			<button id="next" title="下页">
 				<i class="fa fa-arrow-right fa-lg" aria-hidden="true"></i>
 			</button>
-			<span>Page: <input id="page_index" type="text"/> / <span
+			<span>Page: <input id="page_index" type="text" /> / <span
 				id="page_size"></span></span>
 		</div>
 
 
 		<div id="toolbarViewerRight">
-			<button id="print" title="打印" tabindex="1">
+			<button id="print" title="打印">
 				<i class="fa fa-print fa-lg" aria-hidden="true"></i>
 			</button>
-			<button id="download_pdf" title="下载PDF" tabindex="2">
+			<button id="download_pdf" title="下载PDF">
 				<i class="fa fa-file-pdf-o fa-lg" aria-hidden="true"></i>
 			</button>
-			<button id="download_excel" title="下载Excel" tabindex="3"
-				hidden="true">
-				<i class="fa fa-file-excel-o fa-lg" aria-hidden="true"></i>
-			</button>
-			<button id="download_excel_with_only_data" title="下载Excel（仅数据）"
-				tabindex="4">
+			<button id="download_excel_with_only_data" title="下载Excel（仅数据）">
 				<i class="fa fa-file-excel-o fa-lg" aria-hidden="true"></i>
 			</button>
 		</div>

src/main/webapp/resources/css/preview2.css

@@ -12,6 +12,7 @@ button, #toolbarContainer {
 button {
 	border: 0;
 	cursor: pointer;
+	outline: none;
 }
 
 #toolbarContainer {