diff --git a/index.js b/index.js
deleted file mode 100644
index 5cffa97..0000000
--- a/index.js
+++ /dev/null
@@ -1,145 +0,0 @@
-(function (global) {
-  'use strict';
-
-  var storage = global.localStorage;
-  if (storage == null) {
-    // if the localStorage is not exists
-    storage = {
-      // eslint-disable-next-line
-      getItem: function () { return null },
-      setItem: function () { },
-      removeItem: function () { },
-      clear: function () { },
-    };
-  }
-
-  // get the saved bookmark object
-  var getBookmark = function () {
-    var mark = storage.getItem('bookmark');
-    if (mark == null) {
-      return null;
-    }
-    try {
-      return JSON.parse(mark);
-    } catch (e) {
-      // invalid object saved in the storage
-      // console.warn('Invalid bookmark object.');
-      return null;
-    }
-  };
-
-  var link;
-  // register everything
-  var init = function () {
-    // bookmark-link style
-    var style = global.document.createElement('style');
-    style.type = 'text/css';
-    var text = '.book-mark-link{'
-      + 'border-bottom:none;'
-      + 'display:block;'
-      + 'position:fixed;'
-      + 'color:#222;'
-      + 'font-size:26px !important;'
-      + 'top:-10px;left:20px;'
-      + 'transition:.3s;'
-      + '}'
-      + '.book-mark-link:hover,.book-mark-link-fixed{top:-2px}'
-      // do not show when the width is not enough
-      + '@media(max-width:1090px){.book-mark-link{display:none}}';
-    text = global.document.createTextNode(text);
-    style.appendChild(text);
-    global.document.head.appendChild(style);
-
-    // create a link element
-    // eslint-disable-next-line max-len
-    link = $('<a class="book-mark-link book-mark-link-fixed fa fa-bookmark" href="#"></a>');
-    $(global.document.body).append(link);
-
-    var currentTop = 0;
-    // scroll event
-    $(global).on('scroll.bookmark', function () {
-      var top = global.document.documentElement.scrollTop;
-      if (top > 0) {
-        if (currentTop === 0) {
-          link.removeClass('book-mark-link-fixed');
-          currentTop = top;
-        }
-      } else {
-        if (currentTop > 0) {
-          !link.hasClass('book-mark-link-fixed') &&
-            link.addClass('book-mark-link-fixed');
-          currentTop = 0;
-        }
-      }
-    });
-  };
-
-  var loadBookmark = function () {
-    var mark = getBookmark();
-    if (mark == null) {
-      return;
-    }
-    // found the bookmark
-    $(function () {
-      init();
-      link.attr('href', mark.lastUri + '#book:mark');
-    });
-  };
-
-  var doScroll = function (top) {
-    if (!isNaN(top)) {
-      $(function () {
-        // eslint-disable-next-line max-len
-        $(global.document.documentElement).animate({ 'scrollTop': top }, 'fast');
-      });
-    }
-  };
-
-  var doSaveScroll = function (path, mark) {
-    if (mark == null) {
-      mark = {};
-    }
-    var top = global.document.documentElement.scrollTop;
-    mark.lastUri = path;
-    mark[path] = top;
-    storage.setItem('bookmark', JSON.stringify(mark));
-    link.animate({ top: -26 }, 'fast', function () {
-      setTimeout(function () {
-        link.css('top', '');
-      }, 400);
-    });
-    return mark;
-  };
-
-  var scrollToMark = function (trigger, hash) {
-    var path = global.location.pathname;
-    var mark = getBookmark();
-    $(function () {
-      init();
-      // save the position by clicking the icon
-      link.click(function () {
-        mark = doSaveScroll(path, mark);
-        return false;
-      });
-
-      // register beforeunload event when the trigger is auto
-      if (trigger === 'auto') {
-        // register beforeunload event
-        global.addEventListener('beforeunload', function () {
-          doSaveScroll(path, mark);
-        });
-      }
-      // auto scroll to the position
-      // and if the page opens with a specific hash, just jump out
-      if (mark == null || global.location.hash === hash) {
-        return;
-      }
-      doScroll(mark[path]);
-    });
-  };
-
-  global.bookmark = {
-    loadBookmark: loadBookmark,
-    scrollToMark: scrollToMark,
-  };
-})(window);