Virtual keyboard pops up to hide the bottom, otherwise, you can focus on the (onfocus), out-of-focus (onblur) event by monitoring the input box

this is the mobile layout pit. Wrap up your content and add
.main {

  position: fixed;
  top: 0px;
  bottom: 50px;
  overflow-y: scroll;

}

    /**/
    let winHeight = window.innerHeight
    window.addEventListener('resize', function() {
      if (winHeight > window.innerHeight) {
        /**/
        document.getElementsByTagName('body')[0].setAttribute('height', winHeight+'px')
      }else {
        /**/
        document.getElementsByTagName('body')[0].setAttribute('height', '100%')
      }
    })

give it a try.