file-upload.js

//Reference: 
//https://www.onextrapixel.com/2012/12/10/how-to-create-a-custom-file-input-with-jquery-css3-and-php/
;(function($) {

      // Browser supports HTML5 multiple file?
      var multipleSupport = typeof $('<input/>')[0].multiple !== 'undefined',
          isIE = /msie/i.test( navigator.userAgent );

      $.fn.customFile = function() {

        return this.each(function() {

          var $file = $(this).addClass('custom-file-upload-hidden'), // the original file input
              $wrap = $('<div class="file-upload-wrapper">'),
              $input = $('<input type="text" class="file-upload-input" />'),
              // Button that will be used in non-IE browsers
              $button = $('<button type="button" class="file-upload-button">Select a File</button>'),
              // Hack for IE
              $label = $('<label class="file-upload-button" for="'+ $file[0].id +'">Select a File</label>');

          // Hide by shifting to the left so we
          // can still trigger events
          $file.css({
            position: 'absolute',
            left: '-9999px'
          });

          $wrap.insertAfter( $file )
            .append( $file, $input, ( isIE ? $label : $button ) );

          // Prevent focus
          $file.attr('tabIndex', -1);
          $button.attr('tabIndex', -1);

          $button.click(function () {
            $file.focus().click(); // Open dialog
          });

          $file.change(function() {

            var files = [], fileArr, filename;

            // If multiple is supported then extract
            // all filenames from the file array
            if ( multipleSupport ) {
              fileArr = $file[0].files;
              for ( var i = 0, len = fileArr.length; i < len; i++ ) {
                files.push( fileArr[i].name );
              }
              filename = files.join(', ');

            // If not supported then just take the value
            // and remove the path to just show the filename
            } else {
              filename = $file.val().split('\\').pop();
            }

            $input.val( filename ) // Set the value
              .attr('title', filename) // Show filename in title tootlip
              .focus(); // Regain focus

          });

          $input.on({
            blur: function() { $file.trigger('blur'); },
            keydown: function( e ) {
              if ( e.which === 13 ) { // Enter
                if ( !isIE ) { $file.trigger('click'); }
              } else if ( e.which === 8 || e.which === 46 ) { // Backspace & Del
                // On some browsers the value is read-only
                // with this trick we remove the old input and add
                // a clean clone with all the original events attached
                $file.replaceWith( $file = $file.clone( true ) );
                $file.trigger('change');
                $input.val('');
              } else if ( e.which === 9 ){ // TAB
                return;
              } else { // All other keys
                return false;
              }
            }
          });

        });

      };

      // Old browser fallback
      if ( !multipleSupport ) {
        $( document ).on('change', 'input.customfile', function() {

          var $this = $(this),
              // Create a unique ID so we
              // can attach the label to the input
              uniqId = 'customfile_'+ (new Date()).getTime(),
              $wrap = $this.parent(),

              // Filter empty input
              $inputs = $wrap.siblings().find('.file-upload-input')
                .filter(function(){ return !this.value }),

              $file = $('<input type="file" id="'+ uniqId +'" name="'+ $this.attr('name') +'"/>');

          // 1ms timeout so it runs after all other events
          // that modify the value have triggered
          setTimeout(function() {
            // Add a new input
            if ( $this.val() ) {
              // Check for empty fields to prevent
              // creating new inputs when changing files
              if ( !$inputs.length ) {
                $wrap.after( $file );
                $file.customFile();
              }
            // Remove and reorganize inputs
            } else {
              $inputs.parent().remove();
              // Move the input so it's always last on the list
              $wrap.appendTo( $wrap.parent() );
              $wrap.find('input').focus();
            }
          }, 1);

        });
      }

}(jQuery));

$('input[type=file]').customFile();