diff --git a/plugins/calendar/calendar_ui.js b/plugins/calendar/calendar_ui.js
index 110cf6f0..99f9c09f 100644
--- a/plugins/calendar/calendar_ui.js
+++ b/plugins/calendar/calendar_ui.js
@@ -4338,7 +4338,7 @@ window.rcmail && rcmail.addEventListener('init', function(evt) {
         cl += ' active';
       }
 
-      new_btn = $('<button>').attr({'class': cl}).text(btn.text())
+      new_btn = $('<button>').attr({'class': cl, type: 'button'}).text(btn.text())
         .appendTo(selector)
         .on('click', function() {
           activate(this);
@@ -4353,7 +4353,7 @@ window.rcmail && rcmail.addEventListener('init', function(evt) {
 
     $.each(['prev', 'today', 'next'], function() {
       var btn = $('.fc-header-right').find('.fc-button-' + this);
-      $('<button>').attr({'class': 'btn btn-secondary'})
+      $('<button>').attr({'class': 'btn btn-secondary', type: 'button'})
         .text(btn.text()).appendTo(nav).on('click', function() { btn.click(); });
     });
 
diff --git a/plugins/calendar/print.js b/plugins/calendar/print.js
index a469f538..6b7c584c 100644
--- a/plugins/calendar/print.js
+++ b/plugins/calendar/print.js
@@ -186,7 +186,7 @@ window.rcmail && rcmail.addEventListener('init', function(evt) {
         cl += ' active';
       }
 
-      $('<button>').attr({'class': cl})
+      $('<button>').attr({'class': cl, type: 'button'})
         .text(btn.text())
         .appendTo(selector)
           .on('click', function() {
diff --git a/plugins/calendar/skins/elastic/templates/calendar.html b/plugins/calendar/skins/elastic/templates/calendar.html
index c7c6bd6f..bfea051c 100644
--- a/plugins/calendar/skins/elastic/templates/calendar.html
+++ b/plugins/calendar/skins/elastic/templates/calendar.html
@@ -226,15 +226,15 @@
 		class="schedule-table" data-h-margin="-1" data-v-margin="1" />
 	<div class="nav">
 		<div class="schedule-buttons">
-			<button id="schedule-find-prev" class="btn btn-secondary prev-slot"><roundcube:label name="calendar.prevslot" /></button>
-			<button id="schedule-find-next" class="btn btn-secondary next-slot"><roundcube:label name="calendar.nextslot" /></button>
+			<button type="button" id="schedule-find-prev" class="btn btn-secondary prev-slot"><roundcube:label name="calendar.prevslot" /></button>
+			<button type="button" id="schedule-find-next" class="btn btn-secondary next-slot"><roundcube:label name="calendar.nextslot" /></button>
 		</div>
 		<div class="schedule-options">
 			<label><input type="checkbox" id="schedule-freebusy-workinghours" value="1" class="pretty-checkbox" /><roundcube:label name="calendar.onlyworkinghours" /></label>
 		</div>
 		<div class="schedule-nav">
-			<button id="schedule-freebusy-prev" title="<roundcube:label name='previouspage' />">&#9668;</button>
-			<button id="schedule-freebusy-next" title="<roundcube:label name='nextpage' />">&#9658;</button>
+			<button type="button" id="schedule-freebusy-prev" title="<roundcube:label name='previouspage' />">&#9668;</button>
+			<button type="button" id="schedule-freebusy-next" title="<roundcube:label name='nextpage' />">&#9658;</button>
 		</div>
 	</div>
 	<div class="schedule-range">
diff --git a/plugins/calendar/skins/elastic/templates/eventedit.html b/plugins/calendar/skins/elastic/templates/eventedit.html
index 5c89ce42..d0c97e16 100644
--- a/plugins/calendar/skins/elastic/templates/eventedit.html
+++ b/plugins/calendar/skins/elastic/templates/eventedit.html
@@ -141,7 +141,7 @@
 				<h3 id="aria-label-attachmentuploadform" class="voice"><roundcube:label name="arialabelattachmentuploadform" /></h3>
 				<div id="edit-attachments-form" class="upload-form" role="region" aria-labelledby="aria-label-attachmentuploadform">
 					<roundcube:object name="plugin.attachments_form" mode="hint" />
-					<button type="button" class="btn btn-secondary attach" href="#" onclick="rcmail.upload_input('event-attachment-form'); return false"><roundcube:label name="addattachment" /></button>
+					<button type="button" class="btn btn-secondary attach" onclick="rcmail.upload_input('event-attachment-form'); return false"><roundcube:label name="addattachment" /></button>
 				</div>
 				<div id="edit-attachments">
 					<roundcube:object name="plugin.attachments_list" id="attachmentlist" class="attachmentslist" />
diff --git a/plugins/calendar/skins/elastic/templates/print.html b/plugins/calendar/skins/elastic/templates/print.html
index af96fcdd..b560dad4 100644
--- a/plugins/calendar/skins/elastic/templates/print.html
+++ b/plugins/calendar/skins/elastic/templates/print.html
@@ -1,7 +1,7 @@
 <roundcube:include file="includes/layout.html" />
 
 <div class="print-config">
-	<button class="btn btn-primary print" onclick="window.print()"><roundcube:label name='print' /></button>
+	<button type="button" class="btn btn-primary print" onclick="window.print()"><roundcube:label name='print' /></button>
 	<span class="prop">
 		<input type="checkbox" id="propdescription" checked="checked" class="pretty-checkbox" />
 		<label for="propdescription"><roundcube:label name="calendar.printdescriptions" /></label>
diff --git a/plugins/calendar/skins/larry/templates/calendar.html b/plugins/calendar/skins/larry/templates/calendar.html
index a42b985c..d59c299f 100644
--- a/plugins/calendar/skins/larry/templates/calendar.html
+++ b/plugins/calendar/skins/larry/templates/calendar.html
@@ -301,7 +301,7 @@
 	<div class="schedule-options">
 		&nbsp;
 		<div class="schedule-buttons">
-			<button id="schedule-freebusy-prev" title="<roundcube:label name='previouspage' />">&#9668;</button><button id="schedule-freebusy-next" title="<roundcube:label name='nextpage' />">&#9658;</button>
+			<button type="button" id="schedule-freebusy-prev" title="<roundcube:label name='previouspage' />">&#9668;</button><button type="button" id="schedule-freebusy-next" title="<roundcube:label name='nextpage' />">&#9658;</button>
 		</div>
 	</div>
 
@@ -319,8 +319,8 @@
 	</div>
 	<div style="float:left">
 		<div class="schedule-find-buttons">
-			<button id="schedule-find-prev">&#9668; <roundcube:label name="calendar.prevslot" /></button>
-			<button id="schedule-find-next"><roundcube:label name="calendar.nextslot" /> &#9658;</button>
+			<button type="button" id="schedule-find-prev">&#9668; <roundcube:label name="calendar.prevslot" /></button>
+			<button type="button" id="schedule-find-next"><roundcube:label name="calendar.nextslot" /> &#9658;</button>
 		</div>
 		<div class="schedule-options">
 			<label><input type="checkbox" id="schedule-freebusy-workinghours" value="1" /><roundcube:label name="calendar.onlyworkinghours" /></label>
diff --git a/plugins/kolab_files/skins/elastic/templates/compose_plugin.html b/plugins/kolab_files/skins/elastic/templates/compose_plugin.html
index ed3d14da..28f99d2d 100644
--- a/plugins/kolab_files/skins/elastic/templates/compose_plugin.html
+++ b/plugins/kolab_files/skins/elastic/templates/compose_plugin.html
@@ -26,7 +26,7 @@
 				</ul>
 			</div>
 			<div class="formbuttons">
-				<button class="btn btn-primary icon search" href="#" onclick="return rcmail.command('files-search')"><roundcube:label name="search" /></button>
+				<button type="button" class="btn btn-primary icon search" onclick="return rcmail.command('files-search')"><roundcube:label name="search" /></button>
 			</div>
 		</div>
 		<h4 id="aria-label-filelist" class="voice"><roundcube:label name="kolab_files.arialabelfilelist" /></h4>
diff --git a/plugins/kolab_files/skins/elastic/templates/files.html b/plugins/kolab_files/skins/elastic/templates/files.html
index 10606650..92730ba6 100644
--- a/plugins/kolab_files/skins/elastic/templates/files.html
+++ b/plugins/kolab_files/skins/elastic/templates/files.html
@@ -75,7 +75,7 @@
 			</ul>
 		</div>
 		<div class="formbuttons">
-			<button class="btn btn-primary icon search" href="#" onclick="return rcmail.command('files-search')"><roundcube:label name="search" /></button>
+			<button type="button" class="btn btn-primary icon search" onclick="return rcmail.command('files-search')"><roundcube:label name="search" /></button>
 		</div>
 	</div>
 	<div id="filelistcontainer" class="content" role="main" aria-labelledby="aria-label-filelist" data-elastic-mode="true">
diff --git a/plugins/kolab_files/skins/elastic/ui.js b/plugins/kolab_files/skins/elastic/ui.js
index fead9deb..48c23dfa 100644
--- a/plugins/kolab_files/skins/elastic/ui.js
+++ b/plugins/kolab_files/skins/elastic/ui.js
@@ -97,14 +97,14 @@ if (rcmail.env.action == 'open') {
             save_button = $('#filetoolbar a.button.save');
 
         parent.$('.ui-dialog:visible .ui-dialog-buttonpane .ui-dialog-buttonset').prepend(
-            window.editor_save_button = $('<button>')
+            window.editor_save_button = $('<button type="button">')
                 .addClass('save btn btn-secondary' + (save_button.is('.disabled') ? ' hidden' : ''))
                 .text(save_button.text())
                 .on('click', function() { save_button.click(); })
         );
 
         parent.$('.ui-dialog:visible .ui-dialog-buttonpane .ui-dialog-buttonset').prepend(
-            window.editor_edit_button = $('<button>')
+            window.editor_edit_button = $('<button type="button">')
                 .addClass('edit btn btn-secondary' + (edit_button.is('.disabled') ? ' hidden' : ''))
                 .text(edit_button.text())
                 .on('click', function() { edit_button.click(); })
diff --git a/plugins/kolab_tags/kolab_tags.js b/plugins/kolab_tags/kolab_tags.js
index cd61c2e9..ffdd8702 100644
--- a/plugins/kolab_tags/kolab_tags.js
+++ b/plugins/kolab_tags/kolab_tags.js
@@ -263,14 +263,14 @@ function manage_tags()
     var form = $('#tagsform'),
         select = $('select', form),
         buttons = [
-            $('<button class="btn btn-secondary create">')
+            $('<button type="button" class="btn btn-secondary create">')
                 .text(rcmail.gettext('kolab_tags.add'))
                 .click(function() { tag_form_dialog(); }),
-            $('<button class="btn btn-secondary edit">')
+            $('<button type="button" class="btn btn-secondary edit">')
                 .text(rcmail.gettext('kolab_tags.edit'))
                 .attr('disabled', true)
                 .click(function() { tag_form_dialog((select.val())[0]); }),
-            $('<button class="btn btn-danger delete">')
+            $('<button type="button" class="btn btn-danger delete">')
                 .text(rcmail.gettext('kolab_tags.delete'))
                 .attr('disabled', true)
                 .click(function() {
diff --git a/plugins/tasklist/skins/elastic/templates/print.html b/plugins/tasklist/skins/elastic/templates/print.html
index f9ec3190..b9587e28 100644
--- a/plugins/tasklist/skins/elastic/templates/print.html
+++ b/plugins/tasklist/skins/elastic/templates/print.html
@@ -1,7 +1,7 @@
 <roundcube:include file="includes/layout.html" />
 
 <div class="print-config">
-	<button class="btn btn-primary print" onclick="window.print()"><roundcube:label name='print' /></button>
+	<button type="button" class="btn btn-primary print" onclick="window.print()"><roundcube:label name='print' /></button>
 	<span class="prop">
 		<input type="checkbox" id="propdescription" checked="checked" class="pretty-checkbox" onclick="$('#tasklist .description')[this.checked ? 'show' : 'hide']()" />
 		<label for="propdescription"><roundcube:label name="tasklist.printdescriptions" /></label>
diff --git a/plugins/tasklist/skins/elastic/templates/taskedit.html b/plugins/tasklist/skins/elastic/templates/taskedit.html
index 9ba8531e..19699082 100644
--- a/plugins/tasklist/skins/elastic/templates/taskedit.html
+++ b/plugins/tasklist/skins/elastic/templates/taskedit.html
@@ -113,7 +113,7 @@
 				<h3 id="aria-label-attachmentuploadform" class="voice"><roundcube:label name="arialabelattachmentuploadform" /></h3>
 				<div id="taskedit-attachments-form" class="upload-form" role="region" aria-labelledby="aria-label-attachmentuploadform">
 					<roundcube:object name="plugin.attachments_form" mode="hint" />
-					<button type="button" class="btn btn-secondary attach" href="#" onclick="rcmail.upload_input('taskedit-attachment-form'); return false"><roundcube:label name="addattachment" /></button>
+					<button type="button" class="btn btn-secondary attach" onclick="rcmail.upload_input('taskedit-attachment-form'); return false"><roundcube:label name="addattachment" /></button>
 				</div>
 				<div id="taskedit-attachments">
 					<roundcube:object name="plugin.attachments_list" id="taskedit-attachment-list" class="attachmentslist" />