$.fn.ImgZoomIn = function () {
            var window_h = $(window).height();
            var scroll_h = $(window).scrollTop();

            bgstr = '<div id="ImgZoomInBG" style="position: absolute;filter:Alpha(Opacity=70); opacity:0.7;z-index: 10000;background-color: #000;display: none;"></div>';
            imgstr 
 
= '<img id="ImgZoomInImage" src="' + $(this).attr('src')+'" style="cursor:pointer; display:none; position:absolute; z-index:10001;" />';
            if ($('#ImgZoomInBG').length < 1) {
                $('body').append(bgstr);
            }
            if ($('#ImgZoomInImage').length < 1) {
                $(
 
'body').append(imgstr);
            }
            else {
                $('#ImgZoomInImage').attr('src', $(this).attr('src'));
            }

            $('#ImgZoomInBG').css('top', scroll_h+'px');
            $('#ImgZoomInBG').css('width', '100%');
            $('#ImgZoomInBG').css('height', window_h+'px');

            $(
 
'#ImgZoomInImage').css('width', '100%');
            $('#ImgZoomInImage').css('height', (window_h/2)+'px');
            $('#ImgZoomInImage').css('top', (scroll_h+window_h/4)+'px');

            $('#ImgZoomInBG').show();
            $('#ImgZoomInImage').show();
        };

呼叫方法：

/// 點選圖片放大顯示
$(document).on('touchend','.item_img',function (t){
                $(this).ImgZoomIn();
                document.ontouchstart=function(){
                    return false;
                }
                t.preventDefault();
            });
//// 點選隱藏
            $(document).on('touchend','#ImgZoomInImage',function(t){
                $('#ImgZoomInImage').hide();
                $('#ImgZoomInBG').hide();
                document.ontouchstart=function(){
                    return true;
                }
                t.preventDefault();
            });

效果圖：