function PDFCheck(fname) { 
    if(FoundCookie("registration")) { 
        window.open(fname); 
    }
    else {
        alert("You need to enter your email address to access these PDF files.") ; 
    }
} 

function FoundCookie(c_name) { 
   if (document.cookie.length>0) { 
        c_start=document.cookie.indexOf(c_name); 
        if (c_start!=-1) { return true; } 
    } 
    return false; 
}