After the mobile terminal input box acquired focus, the virtual keyboard bounce, also the bottom of the fixed roof up

var homeFootBar = document.querySelector("底部foot")
var shortcutVal = document.querySelector("input")
shortcutVal.addEventListener("focus", function (e) {
    if(navigator.userAgent.match(/(iPhone|iPod|Android|ios)/i)){
        focusInput()
    }
})

/ * Height of the screen * / 
the let docHeight = window.innerHeight // 
function focusInput () { 
    the console.log ( "Andrews phone 2") 
   window.addEventListener ( 'a resize', function () { 
        the console.log ( "Andrews phone 3 ", winHeight +" === "+ window.innerHeight) 
      iF (docHeight> window.innerHeight) { 

         / * Android phone when the keyboard pops up when you set the page height is the height of the screen * /

         = homeFootBar.style.display 'none' 
            the console.log ( "Andrews bottom of the phone disappear") 
            document.getElementsByTagName ( 'body') [0] .setAttribute ( 'height', winHeight + 'PX') 

      } the else { 
         / * when the keyboard retracted * / 
         homeFootBar.style.display = 'Block' 
  
         document.getElementsByTagName ( 'body') [0] .setAttribute ( 'height', '100%') 

      } 

   }) 
}