咋获取不到图片的宽度与高度

Question

 如：   $(function(){
      
       var html="<img src=\"images/about.jpg\" border=\"0\" />";
       $("#div1").append($(html));//把图片添加到div中
       //怎么获取刚添加到div中图片的宽度与高度?
   });  求解各位达人~~~

Answer 1

alert($('#div1 img').css('width'))

Answer 2

这样可以获取到，但是图片去等比缩放时，获取到的宽度却是0,真的很无语.
//等比缩放代码
  function autoSetImgSize(obj) {//圖片自動縮放大小
            var oldWidth = $(obj).width();
            var oldHeight = $(obj).height();
            var saveSize = { w: oldWidth, h: oldHeight, left: 0, top: 0 };
            var defaultSize = { w: 400, h: 350 }; //默認大小
            var wPre = oldWidth / defaultSize.w;
            var hPre = oldHeight / defaultSize.h;
            if (oldWidth > defaultSize.w || oldHeight > defaultSize.h) {
                if (wPre > hPre) {
                    saveSize.w = defaultSize.w;
                    saveSize.h = oldHeight / wPre;
                }
                else {
                    saveSize.w = oldWidth / hPre;
                    saveSize.h = defaultSize.h;
                }
            }
            saveSize.left = (defaultSize.w - saveSize.w) / 2;
            saveSize.top = (defaultSize.h - saveSize.h) / 2;
            //alert(saveSize.w);
            $(obj).css({
                "margin-top": saveSize.top,
                "margin-left": saveSize.left,
                "width": saveSize.w,
                "height": saveSize.h
            });
        }

Answer 3

贴上正确代码:
 function preImageLoad(obj, callback) {
            var img = new Image();
            if ($.browser.msie) {
                img.onreadystatechange = function () {
                    if (this.readyState == "complete") {
                        callback($(obj)[0], { "w": img.width, "h": img.height });
                    }
                }
            } else {
                img.onload = function () {
                    if (this.complete == true) callback($(obj)[0], { "w": img.width, "h": img.height });
                }
            }
            img.src = $(obj).attr("src");
        }

Answer 4

var img = new Image();
img.onload=function(){
alert(img.width +" " +img.height);
};
img.src="images/about.jpg":

Answer 5

  var img = document.getElementById("img");
        var w = img.width;
var h = img.height;