diff --git a/apps/files/js/filelist.js b/apps/files/js/filelist.js
index 29c5a49131..7ba650eb18 100644
--- a/apps/files/js/filelist.js
+++ b/apps/files/js/filelist.js
@@ -1674,7 +1674,7 @@
 							c: fileData.etag
 						};
 					var previewUrl = this.generatePreviewUrl(urlSpec);
-					previewUrl = previewUrl.replace('(', '%28').replace(')', '%29');
+					previewUrl = previewUrl.replace(/\(/g, '%28').replace(/\)/g, '%29');
 					iconDiv.css('background-image', 'url("' + previewUrl + '")');
 				}
 			}
@@ -2058,8 +2058,7 @@
 			}
 
 			previewURL = self.generatePreviewUrl(urlSpec);
-			previewURL = previewURL.replace('(', '%28');
-			previewURL = previewURL.replace(')', '%29');
+			previewURL = previewURL.replace(/\(/g, '%28').replace(/\)/g, '%29');
 
 			// preload image to prevent delay
 			// this will make the browser cache the image
diff --git a/core/js/oc-dialogs.js b/core/js/oc-dialogs.js
index 3583019ef0..c9aeaa0b33 100644
--- a/core/js/oc-dialogs.js
+++ b/core/js/oc-dialogs.js
@@ -280,7 +280,7 @@ var OCdialogs = {
 					self.$form.submit();
 				});
 				var newName = $input.val();
-				lastPos = newName.lastIndexOf('.');
+				var lastPos = newName.lastIndexOf('.');
 				if (lastPos === -1) {
 					lastPos = newName.length;
 				}
diff --git a/core/js/sharedialoglinkshareview.js b/core/js/sharedialoglinkshareview.js
index 91101e47b2..a3d2568463 100644
--- a/core/js/sharedialoglinkshareview.js
+++ b/core/js/sharedialoglinkshareview.js
@@ -245,7 +245,7 @@
 							var $newShare = self.$el.find('li[data-share-id="'+newShareId+'"]');
 							// only open the menu by default if this is the first share
 							if ($newShare && shares.length === 1) {
-								$menu = $newShare.find('.popovermenu');
+								var $menu = $newShare.find('.popovermenu');
 								OC.showMenu(null, $menu);
 							}
 						}
@@ -257,7 +257,7 @@
 					// password failure? Show error
 					self.password = ''
 					if (isPasswordEnforced && response && response.responseJSON && response.responseJSON.ocs.meta && response.responseJSON.ocs.meta.message) {
-						$input = self.$el.find('.pending #enforcedPassText')
+						var $input = self.$el.find('.pending #enforcedPassText')
 						$input.tooltip('destroy');
 						$input.attr('title', response.responseJSON.ocs.meta.message);
 						$input.tooltip({placement: 'bottom', trigger: 'manual'});
diff --git a/core/js/sharedialogview.js b/core/js/sharedialogview.js
index eabcf2f3b2..ffb75f9d15 100644
--- a/core/js/sharedialogview.js
+++ b/core/js/sharedialogview.js
@@ -338,7 +338,7 @@
 						 * build the result array that only contains all contact entries from
 						 * merged contacts, if the search term matches its contact name
 						 */
-						for (i = 0; i < groupedLength; i++) {
+						for (var i = 0; i < groupedLength; i++) {
 							if (typeof grouped[i].uuid !== 'undefined' && grouped[i].uuid === previousUuid) {
 								grouped[i].merged = true;
 							}