function show_div(div_id) {
    document.getElementById(div_id).style.display = 'block';
}
function hide_div(div_id) {
    document.getElementById(div_id).style.display = 'none';
}
var newablak=null;
function winOpen(url,n,width,height){
    var sw=screen.width;
    var sh=screen.height;
    var left=sw?(sw-width)/2:0;
    var top=sh?(sh-height)/2:0;
    newablak=window.open(url,n,"width="+width+",height="+height+",top="+top+",left="+left+",resizable=1,location=0,statusbar=1,toolbar=0,scrollbars=1");
}