JQuery 将元素显示在屏幕的中央的代码

(function($){ 
$.fn.center = function(){ 
var top = ($(window).height() - this.height())/2; 
var left = ($(window).width() - this.width())/2; 
var scrollTop = $(document).scrollTop(); 
var scrollLeft = $(document).scrollLeft(); 
return this.css( { position : 'absolute', 'top' : top + scrollTop, left : left + scrollLeft } ).show(); 
} 
})(jQuery)

调用方法：

$('#dialog').center();