activeSheet.addSpan(0,0,3,3,GC.Spread.Sheets.SheetArea.viewport);

//button click event
var spans= activeSheet.getSpans();      
for(var i = 0; i < spans.length; i++){
alert(spans[i].row);
alert(spans[i].rowCount);
alert(spans[i].col);
alert(spans[i].colCount);
}