function is_email_valid(an_email)
{
    return (an_email.search(/^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/)>=0);
}

function is_empty_str(str)
{
    return (str.toString().replace(/ +/i,"")=="");
}

// окно, которое по центру
function OutInWin(pict, xw, yw, namew,scroll)
{
    var x_width, y_height;
    x_width  = xw;
    y_height = yw;

    if(!scroll) {
        scroll='yes';
    }

    w_top=0; w_left=0;

    w_top = (screen.height - y_height)/2-50;
    w_left= (screen.width - x_width)/2;

    window.open(pict, namew, "top="+w_top+",left="+w_left+",width="+x_width+",height="+y_height+",resizable=yes,scrollbars="+scroll+",status=no,dependent=no");
    return false;
}