function Page() { 

    Page.prototype.readCookie = function readCookie(name) {
                                    var nameEqual = name + "=";
                                    var ca = document.cookie.split(';');
                                    for (var i = 0; i < ca.length; i++) {
                                        var c = ca[i];
                                        while (c.charAt(0) == ' ') {
                                            c = c.substring(1, c.length);
                                        }
                                        if (c.indexOf(nameEqual) == 0) {
                                            return c.substring(nameEqual.length, c.length);
                                        }
                                    }
                                    return null;
                                }


    Page.prototype.createCookie =   function createCookie(name, value, days) {
                                        if (days) {
                                            var date = new Date();
                                            date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
                                            var expires = "; expires=" + date.toGMTString();
                                        }

                                        else expires = "";
                                        document.cookie = name + "=" + value + expires + "; path=/";
                                    }


    Page.prototype.scale =  function scale(x) {
                                w = 100 - 0.0001 * (x);
                                document.getElementById('header').style.width = w + '%';
                            }


    Page.prototype.getStyleSheet =  function getStyleSheet() {
                                        href = document.getElementById("fontsize_css").href;
                                        x = href.lastIndexOf('/') + 1;
                                        y = href.lastIndexOf('.')
                                        cssFileName = href.substring(x, y);
                                        return cssFileName;
                                    }


    Page.prototype.setStyleSheet =  function setStyleSheet(cssFileName) {
                                        href = '/css/textsize/' + cssFileName + '.css';
                                        document.getElementById("fontsize_css").href = href;
                                        return null;
                                    }


    Page.prototype.getPreferredStyleSheet = function getPreferredStyleSheet() {
                                                var i, a;
                                                for (i = 0; (a = document.getElementsByTagName("link")[i]); i++) {
                                                    return a.getAttribute("title");
                                                }
                                                return null;
                                            }

    Page.prototype.changeFontSize = function changeFontSize(fontSize) {
                                        var cssFileName;
                                        switch (fontSize) {
                                            case 1: cssFileName = 'smallfont'; break;
                                            case 2: cssFileName = 'mediumfont'; break;
                                            case 3: cssFileName = 'largefont'; break;
                                        }

                                        href = '/css/textsize/' + cssFileName + '.css';
                                        document.getElementById("fontsize_css").href = href;
                                        this.scale(fontSize);
                                    }

}


var webpage = new Page();

window.onload = function(e) {
    var cookie = webpage.readCookie("style");
    var title = cookie ? cookie : webpage.getStyleSheet();
    if (cookie != null) { webpage.setStyleSheet(title); }
    webpage.scale(4);
}


window.onunload = function(e) {
    var title = webpage.getStyleSheet();
    webpage.createCookie("style", title, 365);
}