diff --git a/layout/_scripts/vendors.swig b/layout/_scripts/vendors.swig
index 95c5344bd1..a64d53240c 100644
--- a/layout/_scripts/vendors.swig
+++ b/layout/_scripts/vendors.swig
@@ -1,11 +1,3 @@
-{# Reset `window.Promise` when it was not a function. #}
-{# IE refers the element whose id is `Promise` as `window.Promise`, this causes Velocity throwing an exception #}
-<script>
-  if (Object.prototype.toString.call(window.Promise) !== '[object Function]') {
-    window.Promise = null;
-  }
-</script>
-
 {% set js_vendors = {} %}
 {% set js_defer_vendors = {} %}
 {% set js_vendors.jquery = 'jquery/index.js?v=3.4.1' %}
diff --git a/layout/_third-party/analytics/lean-analytics.swig b/layout/_third-party/analytics/lean-analytics.swig
index acaf0eb135..9974e01dcc 100644
--- a/layout/_third-party/analytics/lean-analytics.swig
+++ b/layout/_third-party/analytics/lean-analytics.swig
@@ -23,7 +23,7 @@
               })
             {% endif %}
               .fail(function ({ responseJSON }) {
-                console.log('Failed to save Visitor num, with error message: ' + responseJSON.error);
+                console.log(`Failed to save Visitor num, with error message: ${responseJSON.error}`);
               })
           } else {
             {% if theme.leancloud_visitors.security %}
@@ -43,7 +43,7 @@
           }
         })
         .fail(function ({ responseJSON }) {
-          console.log('LeanCloud Counter Error: ' + responseJSON.code + ' ' + responseJSON.error);
+          console.log(`LeanCloud Counter Error: ${responseJSON.code} ${responseJSON.error}`);
         });
     }
     {% else %}
@@ -82,7 +82,7 @@
           }
         })
         .fail(function ({ responseJSON }) {
-          console.log('LeanCloud Counter Error: ' + responseJSON.code + ' ' + responseJSON.error);
+          console.log(`LeanCloud Counter Error: ${responseJSON.code} ${responseJSON.error}`);
         });
     }
     {% endif %}
@@ -93,7 +93,7 @@
           var Counter = function(method, url, data) {
             return $.ajax({
               method: method,
-              url: 'https://' + api_server + '/1.1' + url,
+              url: `https://${api_server}/1.1${url}`,
               headers: {
                 'X-LC-Id': '{{ theme.leancloud_visitors.app_id }}',
                 'X-LC-Key': '{{ theme.leancloud_visitors.app_key }}',
diff --git a/source/js/algolia-search.js b/source/js/algolia-search.js
index ac51950fa7..6f7d5f1dfb 100644
--- a/source/js/algolia-search.js
+++ b/source/js/algolia-search.js
@@ -37,18 +37,12 @@ $(document).ready(function() {
       templates  : {
         item: function(data) {
           var link = data.permalink ? data.permalink : CONFIG.root + data.path;
-          return (
-            '<a href="' + link + '" class="algolia-hit-item-link">'
-          + data._highlightResult.title.value
-          + '</a>'
-          );
+          return `<a href="${link}" class="algolia-hit-item-link">${data._highlightResult.title.value}</a>`;
         },
         empty: function(data) {
-          return (
-            '<div id="algolia-hits-empty">'
-          + algoliaSettings.labels.hits_empty.replace(/\$\{query}/, data.query)
-          + '</div>'
-          );
+          return `<div id="algolia-hits-empty">
+              ${algoliaSettings.labels.hits_empty.replace(/\$\{query}/, data.query)}
+            </div>`;
         }
       },
       cssClasses: {
@@ -63,13 +57,11 @@ $(document).ready(function() {
           var stats = algoliaSettings.labels.hits_stats
             .replace(/\$\{hits}/, data.nbHits)
             .replace(/\$\{time}/, data.processingTimeMS);
-          return (
-            stats
-            + '<span class="algolia-powered">'
-            + '  <img src="' + CONFIG.root + 'images/algolia_logo.svg" alt="Algolia" />'
-            + '</span>'
-            + '<hr />'
-          );
+          return `${stats}
+            <span class="algolia-powered">
+              <img src="${CONFIG.root}images/algolia_logo.svg" alt="Algolia"/>
+            </span>
+            <hr/>`;
         }
       }
     }),
diff --git a/source/js/local-search.js b/source/js/local-search.js
index dd77a75f17..bd932b73ba 100644
--- a/source/js/local-search.js
+++ b/source/js/local-search.js
@@ -97,7 +97,7 @@ $(document).ready(function() {
     slice.hits.forEach(function(hit) {
       result += text.substring(prevEnd, hit.position);
       var end = hit.position + hit.length;
-      result += '<b class="search-keyword">' + text.substring(hit.position, end) + '</b>';
+      result += `<b class="search-keyword">${text.substring(hit.position, end)}</b>`;
       prevEnd = end;
     });
     result += text.substring(prevEnd, slice.end);
@@ -194,15 +194,13 @@ $(document).ready(function() {
           var resultItem = '';
 
           if (slicesOfTitle.length !== 0) {
-            resultItem += '<li><a href="' + articleUrl + '" class="search-result-title">' + highlightKeyword(title, slicesOfTitle[0]) + '</a>';
+            resultItem += `<li><a href="${articleUrl}" class="search-result-title">${highlightKeyword(title, slicesOfTitle[0])}</a>`;
           } else {
-            resultItem += '<li><a href="' + articleUrl + '" class="search-result-title">' + title + '</a>';
+            resultItem += `<li><a href="${articleUrl}" class="search-result-title">${title}</a>`;
           }
 
           slicesOfContent.forEach(function(slice) {
-            resultItem += '<a href="' + articleUrl + '">'
-              + '<p class="search-result">' + highlightKeyword(content, slice)
-              + '...</p></a>';
+            resultItem += `<a href="${articleUrl}"><p class="search-result">${highlightKeyword(content, slice)}...</p></a>`;
           });
 
           resultItem += '</li>';
@@ -291,11 +289,11 @@ $(document).ready(function() {
   function searchFunc() {
     // Start loading animation
     $('body')
-      .append('<div class="search-popup-overlay local-search-pop-overlay">'
-        + '<div id="search-loading-icon">'
-        + '<i class="fa fa-spinner fa-pulse fa-5x fa-fw"></i>'
-        + '</div>'
-        + '</div>')
+      .append(`<div class="search-popup-overlay local-search-pop-overlay">
+          <div id="search-loading-icon">
+            <i class="fa fa-spinner fa-pulse fa-5x fa-fw"></i>
+          </div>
+        </div>`)
       .css('overflow', 'hidden');
     $('#search-loading-icon').css({
       margin      : '20% auto 0 auto',
diff --git a/source/js/next-boot.js b/source/js/next-boot.js
index f03184f5a1..793b6ff434 100644
--- a/source/js/next-boot.js
+++ b/source/js/next-boot.js
@@ -55,10 +55,10 @@ $(document).ready(function() {
     // Initialize Sidebar & TOC Width.
     var scrollbarWidth = NexT.utils.getScrollbarWidth();
     if ($('.site-overview-wrap').height() > (document.body.clientHeight - NexT.utils.getSidebarSchemePadding())) {
-      $('.site-overview').css('width', 'calc(100% + ' + scrollbarWidth + 'px)');
+      $('.site-overview').css('width', `calc(100% + ${scrollbarWidth}px)`);
     }
     if ($('.post-toc-wrap').height() > (document.body.clientHeight - NexT.utils.getSidebarSchemePadding())) {
-      $('.post-toc').css('width', 'calc(100% + ' + scrollbarWidth + 'px)');
+      $('.post-toc').css('width', `calc(100% + ${scrollbarWidth}px)`);
     }
 
     // Initialize Sidebar & TOC Height.
diff --git a/source/js/scrollspy.js b/source/js/scrollspy.js
index 7efacace41..be16bf0f8f 100644
--- a/source/js/scrollspy.js
+++ b/source/js/scrollspy.js
@@ -119,9 +119,7 @@
 
     this.clear();
 
-    var selector = this.selector
-      + '[data-target="' + target + '"],'
-      + this.selector + '[href="' + target + '"]';
+    var selector = `${this.selector}[data-target="${target}"],${this.selector}[href="${target}"]`;
 
     var active = $(selector)
       .parents('li')
diff --git a/source/js/utils.js b/source/js/utils.js
index 195213767a..2a79e989ff 100644
--- a/source/js/utils.js
+++ b/source/js/utils.js
@@ -14,7 +14,7 @@ NexT.utils = {
 
         if ($imageWrapLink.length < 1) {
           var imageLink = $image.attr('data-src') || $image.attr('src');
-          $imageWrapLink = $image.wrap('<a class="fancybox fancybox.image" href="' + imageLink + '" itemscope itemtype="http://schema.org/ImageObject" itemprop="url"></a>').parent('a');
+          $imageWrapLink = $image.wrap(`<a class="fancybox fancybox.image" href="${imageLink}" itemscope itemtype="http://schema.org/ImageObject" itemprop="url"></a>`).parent('a');
           if ($image.is('.post-gallery img')) {
             $imageWrapLink.addClass('post-gallery-img');
             $imageWrapLink.attr('data-fancybox', 'gallery').attr('rel', 'gallery');
@@ -26,7 +26,7 @@ NexT.utils = {
         }
 
         if (imageTitle) {
-          $imageWrapLink.append('<p class="image-caption">' + imageTitle + '</p>');
+          $imageWrapLink.append(`<p class="image-caption">${imageTitle}</p>`);
           // Make sure img title tag will show correctly in fancybox
           $imageWrapLink.attr('title', imageTitle).attr('data-caption', imageTitle);
         }
@@ -135,7 +135,7 @@ NexT.utils = {
       $(window).bind('hashchange', function() {
         var tHash = location.hash;
         if (tHash !== '' && !tHash.match(/%\S{2}/)) {
-          $(tNav + 'li:has(a[href="' + tHash + '"])').addClass('active').siblings().removeClass('active');
+          $(`${tNav}li:has(a[href="${tHash}"])`).addClass('active').siblings().removeClass('active');
           $(tHash).addClass('active').siblings().removeClass('active');
         }
       }).trigger('hashchange');
@@ -305,7 +305,7 @@ NexT.utils = {
   },
 
   getScrollbarWidth: function() {
-    var $div = $('<div />').addClass('scrollbar-measure').prependTo('body');
+    var $div = $('<div/>').addClass('scrollbar-measure').prependTo('body');
     var div = $div[0];
     var scrollbarWidth = div.offsetWidth - div.clientWidth;
     $div.remove();