//@Sheron
var visibleContent  = "content-visible";
var hiddenContent   = "content-hidden";

var activeAnchor    = "btn-sidelinks-active";
var inactiveAnchor  = "btn-sidelinks";

function LoadContent(srcElement, contentId)
{
    var elements = document.getElementsByTagName("div");
    
    for (var i=0; i<elements.length; i++)
    {
        if(elements[i].className == visibleContent)
        {
            //hide all elements which're currently visible
            elements[i].className = hiddenContent;
        }
    }
    
    var elementToShow = document.getElementById(contentId);
    
    if(elementToShow != null)
    {
        //display only the element with id equal to contentId
        elementToShow.className = visibleContent;
    }
    
    MakeActive(srcElement);
}

function MakeActive(srcElement)
{
    var sourceElement = document.getElementById(srcElement);
    
    var elements = document.getElementsByTagName("a");
    
    for (var i=0; i<elements.length; i++)
    {
        if(elements[i].className == activeAnchor)
        {
            //make all anchors which're currently active as inactive
            elements[i].className = inactiveAnchor;
        }
    }
    
    var sourceElement = document.getElementById(srcElement);
    
    if(sourceElement != null)
    {
        //make the anchor tag which's currently clicked as active
        sourceElement.className = activeAnchor;
    }
}