I want to get the multiple selected layers name.

Please try this example...

#target Photoshop
app.bringToFront();
main();
function main(){
if(!documents.length) return;
var selectedLayers = getSelectedLayersIdx();
var selectedLayersNames =[];
for(var a in selectedLayers){
    selectedLayersNames.push(getLayerNameByIndex( Number(selectedLayers) ));
    }
alert("Number of Layers selected = " + selectedLayers.length + "\rLayer Names = " + selectedLayersNames.toString());
}

function getLayerNameByIndex( idx ) { 
    var ref = new ActionReference(); 
    ref.putProperty( charIDToTypeID("Prpr") , charIDToTypeID( "Nm  " )); 
    ref.putIndex( charIDToTypeID( "Lyr " ), idx );
    return executeActionGet(ref).getString(charIDToTypeID( "Nm  " ));; 
};
function getSelectedLayersIdx(){ 
      var selectedLayers = new Array; 
      var ref = new ActionReference(); 
      ref.putEnumerated( charIDToTypeID("Dcmn"), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") ); 
      var desc = executeActionGet(ref); 
      if( desc.hasKey( stringIDToTypeID( 'targetLayers' ) ) ){ 
         desc = desc.getList( stringIDToTypeID( 'targetLayers' )); 
          var c = desc.count 
          var selectedLayers = new Array(); 
          for(var i=0;i<c;i++){ 
            try{ 
               activeDocument.backgroundLayer; 
               selectedLayers.push(  desc.getReference( i ).getIndex() ); 
            }catch(e){ 
               selectedLayers.push(  desc.getReference( i ).getIndex()+1 ); 
            } 
          } 
       }else{ 
         var ref = new ActionReference(); 
         ref.putProperty( charIDToTypeID("Prpr") , charIDToTypeID( "ItmI" )); 
         ref.putEnumerated( charIDToTypeID("Lyr "), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") ); 
         try{ 
            activeDocument.backgroundLayer; 
            selectedLayers.push( executeActionGet(ref).getInteger(charIDToTypeID( "ItmI" ))-1); 
         }catch(e){ 
            selectedLayers.push( executeActionGet(ref).getInteger(charIDToTypeID( "ItmI" ))); 
         } 
      } 
      return selectedLayers; 
};
function selectLayerByIndex(index,add){ 
 add = (add == undefined)  ? add = false : add;
 var ref = new ActionReference();
    ref.putIndex(charIDToTypeID("Lyr "), index);
    var desc = new ActionDescriptor();
    desc.putReference(charIDToTypeID("null"), ref );
       if(add) desc.putEnumerated( stringIDToTypeID( "selectionModifier" ), stringIDToTypeID( "selectionModifierType" ), stringIDToTypeID( "addToSelection" ) ); 
      desc.putBoolean( charIDToTypeID( "MkVs" ), false ); 
   try{
    executeAction(charIDToTypeID("slct"), desc, DialogModes.NO );
}catch(e){}
};