Scroll start/stop events using jQuery

app-code.js

$(function() {

  $(document).on('scrollstart', function() {
    console.log('scroll started')
  })

  $(document).on('scrollend', function() {
    console.log('scroll ended')
  })

})

jquery-scrollstartstop.js

(function() {
  
  var lastScrollAt = Date.now()
    , timeout

  function scrollStartStop() {
      var $this = $(this)
    
      if (Date.now() - lastScrollAt > 100)
          $this.trigger('scrollstart')
        
      lastScrollAt = Date.now()
    
      clearTimeout(timeout)
    
      timeout = setTimeout(function() {
          if (Date.now() - lastScrollAt > 99)
          $this.trigger('scrollend')
      }, 100)
  }
  
  $(document).on('scroll', scrollStartStop)
  
})()