var selectedRow = null;
var selectedRowClassName;
var lastMouseOverRowClassName;

function rowMouseOver(tr, className) 
{
    if (selectedRow == tr)
        return;
    lastMouseOverRowClassName = tr.className;
    tr.className = className;
}

function rowMouseOut(tr) 
{
    if (selectedRow == tr)
        return;
    tr.className = lastMouseOverRowClassName;
}

function rowMouseDown(tr, className) 
{
    if (selectedRow == tr)
        return;
    if (selectedRow != null)
        selectedRow.className = selectedRowClassName;
    selectedRow = tr;
    selectedRowClassName = lastMouseOverRowClassName;
    tr.className = className;
}