Jquery控制图片宽度及高度 ,做到等比例缩放

$(document).ready(function() {  
            var maxWidth = 780;  
            var maxHeight = 500;  
            var zoomTimes;  
            $("img").each(function(){             
                    var curWidth  = $(this).width();  
                    var curHeight = $(this).height();  
                    if(curWidth > maxWidth){  
                         $(this).width(maxWidth);  
                         zoomTimes=curWidth/maxWidth;  
                         $(this).height(curHeight/zoomTimes);  
                    }else if(curHeight > maxHeight){  
                         $(this).height(maxHeight);  
                         zoomTimes=curHeight/maxHeight;  
                         $(this).width(curWidth/zoomTimes);  
                    }  
                });  
        });