var displayfirst = 1;
var displaylast = 5; //no of elements to display
function back()
{
    if(count > 5) // 5 is number of images we are dislaying
    {
        document.getElementById("right_scroll").className = "right_scroll_on";
    }

    if(displayfirst != 1)
    {
        var start = --displayfirst;
        var end = --displaylast;

        for(var i = 1; i <= count; i++)
        {

            if(i >= start && i <= end)
            {
                document.getElementById('id_'+i).style.display = 'inline';

            }
            else
            {
                document.getElementById('id_'+i).style.display = 'none';
            }

        }
    }
    if(displayfirst == 1)
    {

        document.getElementById("left_scroll").className = "left_scroll_off";
    }

}

function forward()
{
    if(count > 5) // 5 is number of images we are dislaying
    {
        document.getElementById("left_scroll").className = "left_scroll_on";
    }

    if(displaylast != count)
    {
        var start = ++displayfirst;
        var end = ++displaylast;

        for(var i = 1; i <= count; i++)
        {

            if( i >= start && i <= end)
            {
                document.getElementById('id_'+i).style.display = 'inline';
            }
            else
            {
                document.getElementById('id_'+i).style.display = 'none';
            }
        }
    }
    if(displaylast == count)
    {
        document.getElementById("right_scroll").className = "right_scroll_off";
    }
}

function setScrollerToItem(id){
    for(var i=displaylast; i < id; i++)
        forward();
}
function previous_next_item_mouse_over(x, v)
{
    if(v == "previous_item_over"){
        if(document.getElementById('previous_item') != null &&
                document.getElementById('previous_item').className != "previous_item_on")
            document.getElementById('previous_item').className =  "previous_item_on";
    }
    if(v == "next_item_over"){
        if(document.getElementById('next_item') != null &&
                document.getElementById('next_item').className != "next_item_on")
            document.getElementById('next_item').className =  "next_item_on";
    }
}

function previous_next_item_mouse_out(){
    if(document.getElementById('previous_item') != null)
        document.getElementById('previous_item').className = 'previous_item_off';
    if(document.getElementById('next_item') != null)
        document.getElementById('next_item').className = 'next_item_off';
}