jQuery.fn.center = function () {
	this.css("position","absolute");
	this.css({position: 'absolute',top:'50%',left:'50%',margin:'-'+(this.height() / 2)+'px 0 0 -'+(this.width() / 2)+'px'});
	if($.browser.mozilla) {
		this.css('top', $(document).scrollTop()+100 + 'px');
	} else {
		this.css('top', $(document).scrollTop()+300 + 'px');
	}
	return this;
}

jQuery.fn.center2 = function () {
	this.css("position","absolute");
	this.css({position: 'absolute',top:'50%',left:'51%',margin:'-'+(this.height() / 2)+'px 0 0 -'+(this.width() / 2)+'px'});
	if($.browser.mozilla) {
		this.css('top', $(document).scrollTop()+305 + 'px');
	} else { 
		this.css('top', $(document).scrollTop()+325 + 'px');
	}
	return this;
}