code: function createIcons(elem, data) {
          var sites = getSites(data);
          var isPrepend = data.mode == 'prepend';
  
          each(isPrepend ? sites.reverse() : sites, function (name) {
              var url = makeUrl(name, data);
              var link = data.initialized ? getElementsByClassName(elem, 'icon-' + name) : createElementByString('<a class="social-share-icon icon-' + name + '"></a>');
  
              if (!link.length) {
                  return true;
              }
  
              link[0].href = url;
  
              if (name === 'wechat') {
                  link[0].tabindex = -1;
              } else {
                  link[0].target = '_blank';
              }
  
              if (!data.initialized) {
                  isPrepend ? elem.insertBefore(link[0], elem.firstChild) : elem.appendChild(link[0]);
              }
          });
      }
docs: Create site icons
  
  @param {Element} elem
  @param {Object} data