Photoshop script that selects the next layer above or below even if it's not visible.

Select Next Layer (invisible or not).jsx

// Select Next Layer (invisible or not).jsx
// https://gist.github.com/joonaspaakko/048c9b58ccbb6e6f44c894bf4ce30b68

nextLayer('down');

// direction (↑): "up" or "above"
// direction (↓): "down" or "below"
function nextLayer( direction ) {
  
  var doc = app.activeDocument;
   // Doc duplication is necessary because while the History panel can record visibility change, but for some reason it doesn't do that when the visibility command comes from a script... (AFAIK)
  var tempDoc = doc.duplicate();
  var layer1 = tempDoc.activeLayer;
  
  // Turn background layer into a normal layer
  var lastLayer = tempDoc.layers[ tempDoc.layers.length-1 ];
  function cTID(s) { return app.charIDToTypeID(s); };
  function sTID(s) { return app.stringIDToTypeID(s); };
  var layer1ID = activeLayerID();
  tempDoc.activeLayer = lastLayer;
  var bgLayerExists = lastLayer.isBackgroundLayer;
  if ( bgLayerExists ) { lastLayer.isBackgroundLayer = false; }
  try { selectLayerByID( layer1ID ); } catch(e) {}
  // Select all layers
  var desc23 = new ActionDescriptor();
  var ref5 = new ActionReference();
  ref5.putEnumerated( cTID('Lyr '), cTID('Ordn'), cTID('Trgt') );
  desc23.putReference( cTID('null'), ref5 );
  executeAction( sTID('selectAllLayers'), desc23, DialogModes.NO );
  // Make active layers visible
  var desc209 = new ActionDescriptor();
  var list93 = new ActionList();
  var ref129 = new ActionReference();
  ref129.putEnumerated( cTID('Lyr '), cTID('Ordn'), cTID('Trgt') );
  list93.putReference( ref129 );
  desc209.putList( cTID('null'), list93 );
  executeAction( cTID('Shw '), desc209, DialogModes.NO );
  // Reselect the starting layer
  if ( bgLayerExists ) { lastLayer.isBackgroundLayer = true; }
  selectLayerByID( layer1ID );
  // Select next layer
  try { snl( direction ); } catch(e) {}
  // Store the layer
  var nextLayer = activeLayerID();
  tempDoc.close( SaveOptions.DONOTSAVECHANGES );
  // Try to select the next layer using its ID
  try {
    selectLayerByID( nextLayer );
  }
  // If it fails, well assume it did so because it was a background layer... and use another method for selecting that.
  catch(e) {
    var desc299 = new ActionDescriptor();
        var ref187 = new ActionReference();
        ref187.putName( cTID('Lyr '), "Background" );
    desc299.putReference( cTID('null'), ref187 );
    desc299.putBoolean( cTID('MkVs'), false );
        var list138 = new ActionList();
        list138.putInteger( 1 );
    desc299.putList( cTID('LyrI'), list138 );
    executeAction( cTID('slct'), desc299, DialogModes.NO );
  }
  
  function snl( direction ) {
    
    var select;
    if ( direction == 'up' || direction == 'above' ) {
      select = cTID('Frwr');
    }
    else if ( direction == 'down' || direction == 'below' ) {
      select = cTID('Bckw');
    }
    
    var desc67 = new ActionDescriptor();
    var ref41 = new ActionReference();
    ref41.putEnumerated( cTID('Lyr '), cTID('Ordn'), select );
    desc67.putReference( cTID('null'), ref41 );
    desc67.putBoolean( cTID('MkVs'), false );
    var list17 = new ActionList();
    list17.putInteger( 5 );
    desc67.putList( cTID('LyrI'), list17 );
    executeAction( cTID('slct'), desc67, DialogModes.NO );
  }
  
  function activeLayerID() {
      var ref = new ActionReference();
      ref.putProperty( charIDToTypeID("Prpr") , charIDToTypeID( "LyrI" ));
      ref.putEnumerated( charIDToTypeID("Lyr "), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") );
  	return executeActionGet(ref).getInteger( stringIDToTypeID( "layerID" ) );
  }
  
  function selectLayerByID(id, add){
     add = (add == undefined) ? add = false : add;
     var ref = new ActionReference();
     ref.putIdentifier(cTID('Lyr '), id);
     var desc = new ActionDescriptor();
     desc.putReference(cTID('null'), ref);
     if(add){
        desc.putEnumerated(sTID('selectionModifier'), sTID('selectionModifierType'), sTID('addToSelection'));
     }
     desc.putBoolean(cTID('MkVs'), false);
     executeAction(cTID('slct'), desc, DialogModes.NO);
  }
  
}

@methodphoto, my guess is that there shouldn't be any issues going forward. Most of the script is Action Manager code, which is typically pretty solid, though it's not unheard of for those things to break. This script is from 2019, so there have already been quite a few new versions since. Just tested it in CC 2023 and it seemed to work fine.

you can't imagine how long I've been looking for this script! it works great! THANK YOU!!!🔝

I am also in gratitude over here too, for thy sharing of this .jsx script, which effectively fixed a longstanding scripting issue I have been having for a while, MUCHAS GRACIAS!

How do I use this? I've gotten as far as locating the .jsx file and loading it, pressing alt + , [ or ] to switch between layers but it still skips the hidden ones. I have never used a single script before and am so stumped at this.

@Dorgarge222, here's one way to assign a keyboard shortcut to launch a script: https://youtu.be/_-4A2EPjglA. In this case though, if you look at line 4 the script is currently set to go down a layer. You need to duplicate the file, change it to go up and assign different shortcuts for each script file.

That said, on a mac I tend to launch all my scripts through a Mac app called Alfred. Either by setting a shortcut to open the script file in Photoshop or by using this file filter.

Thank you so much!