How to add layer mask?

[Guest]

Must add each layer of the document (except the background) mask blank:

There is such a script:

if(app.documents.length>0){
    var docRef = activeDocument;
    var layerNum = docRef.layers.length;

    for(var i=0;i<layerNum;i++){
        docRef.activeLayer = docRef.layers;
        if(!docRef.activeLayer.isBackgroundLayer){
            try{addMask ()}
            catch(e){}
            }
        }
    }
else{alert('There are no open files')};

function addMask(){
    var idMk = charIDToTypeID( "Mk  " );
        var desc2 = new ActionDescriptor();
        var idNw = charIDToTypeID( "Nw  " );
        var idChnl = charIDToTypeID( "Chnl" );
        desc2.putClass( idNw, idChnl );
        var idAt = charIDToTypeID( "At  " );
            var ref1 = new ActionReference();
            var idChnl = charIDToTypeID( "Chnl" );
            var idChnl = charIDToTypeID( "Chnl" );
            var idMsk = charIDToTypeID( "Msk " );
            ref1.putEnumerated( idChnl, idChnl, idMsk );
        desc2.putReference( idAt, ref1 );
        var idUsng = charIDToTypeID( "Usng" );
        var idUsrM = charIDToTypeID( "UsrM" );
        var idHdAl = charIDToTypeID( "HdAl" );
        desc2.putEnumerated( idUsng, idUsrM, idHdAl );
    executeAction( idMk, desc2, DialogModes.NO );
}

It runs and adds a mask, but it is filled with black:

How to change the code to create an empty mask (like in the first picture)?

Sorry for my english...

[Muppet Mark · Accepted solution]

Line 30 you have the actionmanager "HdAl" hide all… Record again using show all…?

[Guest]

Thank you very much

[Muppet Mark]

Personly I would add argument to the function so I could pass the 4 options...