网页上图片点击放大js代码

//图片弹出事件
function showPict(path) {
    src = path;
    var mask =
            "<div style = 'position: absolute; 100%;z-index: 5555;height: 100%;top: 0;left: 0;background: rgba(0,0,0,0.5);display:none;' id='imgZoomMask'></div>";
    $("html").append(mask);
    var windowWidth = $(window).width();
    var windowHeight = $(window).height();
    $(window).resize(function () {
        windowWidth = $(window).width();
        windowHeight = $(window).height();
    });
    $("#imgZoomMask").show();

    $(window).resize(function () {
        windowWidth = $(window).width();
        windowHeight = $(window).height();
    });
    var img = new Image();
    img.src = path;
    img.onload = function () {
        var dom = "";
        var displayWidth = 0;
        var displayHeight = 0;
        var style = "";
        if (img.width > img.height) {
            displayWidth = windowWidth / 2;
            displayHeight = img.height * displayWidth / img.width;
            style = "z-index:6666;position:absolute;top:" +
                windowHeight / 2 +
                "px;margin-top:-" +
                displayHeight / 2 +
                "px;left:" +
                windowWidth / 2 +
                "px;margin-left:-" +
                displayWidth / 2 +
                "px;cursor:pointer;";
            dom = "<img draggable='true' src = '" +
                src +
                "' width = '50%' style='" +
                style +
                "' id='imgZoomImg'>";
        } else {
            displayHeight = windowHeight / 2;
            displayWidth = displayHeight * img.width / img.height;
            style = "z-index:6666;position:absolute;top:" +
                windowHeight / 2 +
                "px;margin-top:-" +
                displayHeight / 2 +
                "px;left:" +
                windowWidth / 2 +
                "px;margin-left:-" +
                displayWidth / 2 +
                "px;cursor:pointer;";
            dom = "<img draggable='true' src = '" +
                src +
                "' height = '50%' style=' " +
                style +
                "' id='imgZoomImg'>";
        }
        $("body").append(dom);
        $("#imgZoomImg").dragging({
            move: "both", //拖动方向，x y both
            randomPosition: false //初始位置是否随机
        });

    }
    $(document).on("click", "#imgZoomMask", function () {
        $("#imgZoomMask").hide();
        $("#imgZoomImg").fadeOut().remove();
    });
    $(document).on("mousewheel", function (e, d) {
        //d 1 上 -1 下
        if (d === 1) {
            var width = $("#imgZoomImg").width();
            var height = $("#imgZoomImg").height();
            $("#imgZoomImg").css({ "width": width * 1.2, "height": height * 1.2 });
        }
        if (d === -1) {
            var width = $("#imgZoomImg").width();
            var height = $("#imgZoomImg").height();
            $("#imgZoomImg").css({ "width": width / 1.2, "height": height / 1.2 });
        }
    });
}