z-song laravel-admin unable load js fucntion untill use f5 code example

Example 1: z-song laravel-admin unable load js fucntion untill use f5

$(document).on('pjax:start', function() {
  alert ('leaving the page. Are you sure?');
})

Example 2: z-song laravel-admin unable load js fucntion untill use f5

$(document).on('pjax:end', function() {
  alert ('page just finished loading');
})