jQuery.fn.center = function () { 
    this.css("position","absolute"); 
    this.css("top", ( $(window).height() - this.height() ) / 2 - 100 + "px"); 
    this.css("left", ( $(window).width() - this.width() ) / 2 + $(window).scrollLeft() + "px"); 
    return this; 
}

jQuery.fn.fullscreen = function () { 
    this.css("position","absolute"); 
    this.css("width", $(window).width() + "px"); 
    this.css("height", $(window).height() + "px"); 
	this.css("overflow","hidden");
    return this; 
}