main(); 
  
function main () { 
    var mybookmarks =app.documents[0].bookmarks.everyItem(); 
    var mybookmarkslen =app.documents[0].bookmarks.length; 
    alert("Deleting " + mybookmarkslen + " bookmarks from document."); 
    for (var i = 0; i < mybookmarkslen; i++) { 
        app.documents[0].bookmarks[i].remove(); 
        } 
 
} 

main();  
   
function main () { 
  var curDoc = app.activeDocument; 
  var allBms = curDoc.bookmarks.everyItem().getElements(); 
  var nBMs = allBms.length; 
  var list = []; 
 
  for (var i = nBMs-1; i >= 1; i--) { 
    var curBm = allBms[i]; 
    var prevBm = allBms[i-1]; 
    if (curBm.name == prevBm.name) { 
      list.push(curBm.id); 
    }        
  }  
  for (i = list.length-1; i > 0; i--) { 
    curDoc.bookmarks.itemByID(list[i-1]).remove();     
  } 
} 

/** 
* @@@BUILDINFO@@@ RemoveBookmarksWithSameName-Uwe-Laubender.jsx !Version! Fri Jun 15 2018 12:02:00 GMT+0200 
*/ 
 
/* 
	Keep the first bookmark that is with a distinct name. 
	Remove all following ones with the same name. 
*/ 
 
app.doScript 
( 
 
	main,  
	ScriptLanguage.JAVASCRIPT,  
	[], 
	UndoModes.ENTIRE_SCRIPT,  
	"Remove bookmarks that follow with the same name | Uwe | SCRIPT" 
 
); 
 
 
function main(){  
 
	if( app.documents.length == 0 ){ return }; 
	if( app.documents[0].bookmarks.length == 0 ){ return }; 
	 
	var doc = app.documents[0]; 
	var bookmarks = doc.bookmarks.everyItem().getElements(); 
	var bookmarksLength = bookmarks.length; 
	 
	var uniqueNames = [] ; 
	var toRemoveByID = [] ; 
 
	for( var n=0;n<bookmarksLength;n++ ) 
	{ 
		if( uniqueNames[ bookmarks[n].name ] == null ) 
		{ 
			uniqueNames[ bookmarks[n].name ] = bookmarks[n].id; 
		} 
	}; 
 
	for( var n=0;n<bookmarksLength;n++ ) 
	{ 
		var currentValue = uniqueNames[ bookmarks[n].name ]; 
		if( currentValue == bookmarks[n].id ){ continue }; 
		 
		toRemoveByID.push( bookmarks[n].id ); 
	}; 
 
	for( var n=0;n<toRemoveByID.length;n++ ) 
	{ 
		doc.pageItems.itemByID( toRemoveByID[n] ).remove(); 
	}; 
 
};