function insertGreyboxPrintSheet()
{
    var cssNode = document.createElement('link');
    cssNode.type = 'text/css';
    cssNode.rel = 'stylesheet';
    cssNode.id = 'greyboxPrintSheet';
    cssNode.href = GB_ROOT_DIR+'print_style.css';
    cssNode.media = 'print';
    cssNode.title = 'to allow printing of greybox only';
    document.getElementsByTagName("head")[0].appendChild(cssNode);
}
function removeGreyboxPrintSheet()
{
    var it = document.getElementById('greyboxPrintSheet');
    it.parentNode.removeChild(it);
}