function changeFont(fontsize) {
                                    
                                    var fnt_normal = document.getElementById('fnt_normal');
                                    var fnt_bigger = document.getElementById('fnt_bigger');
                                    var fnt_biggest = document.getElementById('fnt_biggest');
                                    
                                    switch (fontsize) {
                                        case 'normal': 
                                            document.body.style.fontSize = '12px'; 
                                            SetCookie('font-size', 'normal');
                                            fnt_normal.style.textDecoration = 'underline';
                                            fnt_bigger.style.textDecoration = 'none';
                                            fnt_biggest.style.textDecoration = 'none';  
                                            break;
                                        case 'bigger': 
                                            document.body.style.fontSize = '14px'; 
                                            SetCookie('font-size', 'bigger'); 
                                            fnt_normal.style.textDecoration = 'none';
                                            fnt_bigger.style.textDecoration = 'underline';
                                            fnt_biggest.style.textDecoration = 'none';
                                            break;
                                        case 'biggest': 
                                            document.body.style.fontSize = '16px'; 
                                            SetCookie('font-size', 'biggest');
                                            fnt_normal.style.textDecoration = 'none';
                                            fnt_bigger.style.textDecoration = 'none';
                                            fnt_biggest.style.textDecoration = 'underline'; 
                                            break;
                                    }
                                }
                                function getCookieVal (offset) { 
                                    var endstr = document.cookie.indexOf (";", offset); 
                                    if (endstr == -1) 
                                    endstr = document.cookie.length; 
                                    return unescape(document.cookie.substring(offset, endstr));
                                }
                                function GetCookie (name) { 
                                    var arg = name + "="; 
                                    var alen = arg.length; 
                                    var clen = document.cookie.length; 
                                    var i = 0; 
                                    while (i < clen) { 
                                        var j = i + alen; 
                                        if (document.cookie.substring(i, j) == arg) return getCookieVal (j); 
                                        i = document.cookie.indexOf(" ", i) + 1; 
                                        if (i == 0) break; 
                                    } 
                                    return null;
                                }
                                function SetCookie (name, value) { 
                                    var argv = SetCookie.arguments; 
                                    var argc = SetCookie.arguments.length; 
                                    var expires = (argc > 2) ? argv[2] : null; 
                                    var path = (argc > 3) ? argv[3] : null; 
                                    var domain = (argc > 4) ? argv[4] : null; 
                                    var secure = (argc > 5) ? argv[5] : false; 
                                    document.cookie = name + "=" + escape (value) + 
                                        ((expires == null) ? "" : ("; expires=" + expires.toGMTString())) + 
                                        ((path == null) ? "" : ("; path=" + path)) + 
                                        ((domain == null) ? "" : ("; domain=" + domain)) + 
                                        ((secure == true) ? "; secure" : "");
                                }