How to break link to cell/table style in a selection

I can break link to cell/table style in a current document, but if I want to do it in a selection, it seem error, anyone would help me to fix it?

Script A (For Document is ok)

BreakLinkToCellStyleDocument();

function BreakLinkToCellStyleDocument(){
    var myDoc = app.activeDocument;
    myCells = myDoc.stories.everyItem().tables.everyItem().cells.everyItem().getEle ments();
    for (var i=0; i<myCells.length; i++){
        myCell = myCells[i];
        myCell.appliedCellStyle = myDoc.cellStyles.item(0), false;

            }
        }

Script B (For Selection occur error)

BreakLinkToCellStyleSelection();

function BreakLinkToCellStyleSelection(){
    var myDoc = app.selection[0];
    myCells = myDoc.tables.everyItem().cells.everyItem().getElements();
    for (var i=0; i<myCells.length; i++){
        myCell = myCells[i];
        myCell.appliedCellStyle = myDoc.cellStyles.item(0), false;
        }
    }