var scrollAmount = 100;

function DecreaseScrollRight(scrollerContainerID)
{
    var scrollerContainer = document.getElementById(scrollerContainerID);
    scrollerContainer.scrollLeft = scrollerContainer.scrollLeft - scrollAmount;
//document.getElementById('portfolioItems').scrollLeft = 50;
}

function IncreaseScrollRight(scrollerContainerID)
{
    var scrollerContainer = document.getElementById(scrollerContainerID);
    scrollerContainer.scrollLeft = scrollerContainer.scrollLeft + scrollAmount;
//alert(scrollerContainer.scrollLeft);
//document.getElementById('portfolioItems').scrollLeft = 50;
}