function findPosY(obj) {
        var curtop = 0;
        if (obj.offsetParent) {
                while (obj.offsetParent) {
                        curtop += obj.offsetTop
                        obj = obj.offsetParent;
                }
        }
        else if (obj.y)
                curtop += obj.y;
        return curtop;
}

function getElementSetByIdBase(idBase) {
 
    var elements = new Array(); 
    for(var i=0; i < 6; ++i) {
        var elementId = idBase + i;  
        elements[i] = document.getElementById(elementId);
    }
 
    return elements;
}
 

function getElementsYPos(idBase, 
                         startElementNumber,
                         elementCount,
                         positionIsAbsolute) {
    
    var elements = getElementSetByIdBase(idBase);  
    var yPositions = new Array(elements.length);
 
    for (var i=startElementNumber; i < startElementNumber + elementCount; ++i) {
        var element = elements[i];
        if (positionIsAbsolute) {
            yPositions[i-startElementNumber] = findPosY(element);
        } else {
            yPositions[i-startElementNumber] = element.offsetTop;
        }
    }
    
    return yPositions;
}
 
function maximum(values) {
    var max = 0;
 
    for (var i = 0; i < values.length; ++i) {
        if (values[i] > max) {
            max = values[i];
        }
    }
    return max;
}