//图片等比例压缩

 

    var scaleImage = function (w, h, o) {

        var img = new Image();

        //img.height=$("#imgBig").height();

        //img.width=$("#imgBig").width();

        img.src = o.src;

        if (img.width > 0 && img.height > 0) {

            if (img.width / img.height >= w / h) {

                if (img.width > w) {

                    o.width = w;

                    o.height = (img.height * w) / img.width;

                } else {

                    o.width = img.width;

                    o.height = img.height;

                }

                o.alt = img.width + "x" + img.height;

            } else {

                if (img.height > h) {

                    o.height = h;

                    o.width = (img.width * h) / img.height;

                } else {

                    o.width = img.width;

                    o.height = img.height;

                }

                o.alt = img.width + "x" + img.height;

            }

        }

    }

 

 

 //图片加载完成以后再进行缩放

            document.getElementById("imgBig").onload = function () {

            //调用图片压缩

                scaleImage(734, 450, document.getElementById("imgBig"));

                          }