old_contents: /**
   * some JavaScript code for this blog theme
   */
  /* jshint asi:true */
  
  /////////////////////////header////////////////////////////
  /**
   * clickMenu
   */
  (function() {
      if (window.innerWidth <= 2048) {
          var menuBtn = document.querySelector('#headerMenu')
          var nav = document.querySelector('#headerNav')
          menuBtn.onclick = function(e) {
              e.stopPropagation()
              if (menuBtn.classList.contains('active')) {
                  menuBtn.classList.remove('active')
                  nav.classList.remove('nav-show')
              } else {
                  nav.classList.add('nav-show')
                  menuBtn.classList.add('active')
              }
          }
          document.querySelector('body').addEventListener('click', function() {
              nav.classList.remove('nav-show')
              menuBtn.classList.remove('active')
          })
      }
  }());
  
  
  //////////////////////////back to top////////////////////////////
  (function() {
      var backToTop = document.querySelector('.back-to-top')
      var backToTopA = document.querySelector('.back-to-top a')
          // console.log(backToTop);
      window.addEventListener('scroll',function () {
  
  
          // 页面顶部滚进去的距离
          var scrollTop = Math.max(document.documentElement.scrollTop, document.body.scrollTop)
  
          if (scrollTop > 100) {
              backToTop.classList.add('back-to-top-show')
          } else {
              backToTop.classList.remove('back-to-top-show')
          }
      })
  
      // backToTopA.addEventListener('click',function (e) {
      //     e.preventDefault()
      //     window.scrollTo(0,0)
      // })
  }());
  
  
  //////////////////////////hover on demo//////////////////////////////
  (function() {
      var demoItems = document.querySelectorAll('.grid-item')
  }());
  
new_contents: /**
   * some JavaScript code for this blog theme
   */
  /* jshint asi:true */
  
  /////////////////////////header////////////////////////////
  /**
   * clickMenu
   */
  (function() {
      if (window.innerWidth <= 770) {
          var menuBtn = document.querySelector('#headerMenu')
          var nav = document.querySelector('#headerNav')
          menuBtn.onclick = function(e) {
              e.stopPropagation()
              if (menuBtn.classList.contains('active')) {
                  menuBtn.classList.remove('active')
                  nav.classList.remove('nav-show')
              } else {
                  nav.classList.add('nav-show')
                  menuBtn.classList.add('active')
              }
          }
          document.querySelector('body').addEventListener('click', function() {
              nav.classList.remove('nav-show')
              menuBtn.classList.remove('active')
          })
      }
  }());
  
  
  //////////////////////////back to top////////////////////////////
  (function() {
      var backToTop = document.querySelector('.back-to-top')
      var backToTopA = document.querySelector('.back-to-top a')
          // console.log(backToTop);
      window.addEventListener('scroll',function () {
  
  
          // 页面顶部滚进去的距离
          var scrollTop = Math.max(document.documentElement.scrollTop, document.body.scrollTop)
  
          if (scrollTop > 100) {
              backToTop.classList.add('back-to-top-show')
          } else {
              backToTop.classList.remove('back-to-top-show')
          }
      })
  
      // backToTopA.addEventListener('click',function (e) {
      //     e.preventDefault()
      //     window.scrollTo(0,0)
      // })
  }());
  
  
  //////////////////////////hover on demo//////////////////////////////
  (function() {
      var demoItems = document.querySelectorAll('.grid-item')
  }());
  
subject: test on IPAD air