I want to cancel that add new rows. What should I do ?? Help me

I want to cancel that add new row.
I use this function for add new row.
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obj.newRow = function() {
obj.setRowProperty("count", obj.getRowProperty("count") + 1);
obj.myData[obj.myData.length] = ["","","","","","","","","","",""];
obj.refresh();
}
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and I want to make a 'cancel' function.
'cancel' function is that cancel a 'newRow' fucntion.

thanks!!