filechooser.onchange = function () {if (!this.files.length) return;var files = Array.prototype.slice.call(this.files);if (files.length > 9) {alert("最多同时只可上传9张图片");return;}files.forEach(function (file, i) {if (!/\/(?:jpeg|png|gif)/i.test(file.type)) return;var reader = new FileReader();var li = document.createElement("li");li.innerHTML = '<div class="progress"><span></span></div>';$(".img-list").append($(li));reader.onload = function () {var result = this.result;var img = new Image();img.src = result;//如果图片大小小于200kb，则直接上传if (result.length <= maxsize) {$(li).css("background-image", "url(" + result + ")");img = null;upload(result, file.type, $(li));return;}//                图片加载完毕之后进行压缩，然后上传if (img.complete) {callback();} else {img.onload = callback;}function callback() {var data = compress(img);$(li).css("background-image", "url(" + data + ")");upload(data, file.type, $(li));img = null;}};reader.readAsDataURL(file);})};

function compress(img) {var initSize = img.src.length;var width = img.width;var height = img.height;//如果图片大于四百万像素，计算压缩比并将大小压至400万以下var ratio;if ((ratio = width * height / 4000000)>1) {ratio = Math.sqrt(ratio);width /= ratio;height /= ratio;}else {ratio = 1;}canvas.width = width;canvas.height = height;//        铺底色ctx.fillStyle = "#fff";ctx.fillRect(0, 0, canvas.width, canvas.height);//如果图片像素大于100万则使用瓦片绘制var count;if ((count = width * height / 1000000) > 1) {count = ~~(Math.sqrt(count)+1); //计算要分成多少块瓦片//            计算每块瓦片的宽和高var nw = ~~(width / count);var nh = ~~(height / count);tCanvas.width = nw;tCanvas.height = nh;for (var i = 0; i < count; i++) {for (var j = 0; j < count; j++) {tctx.drawImage(img, i * nw * ratio, j * nh * ratio, nw * ratio, nh * ratio, 0, 0, nw, nh);ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh);}}} else {ctx.drawImage(img, 0, 0, width, height);}//进行最小压缩var ndata = canvas.toDataURL('image/jpeg', 0.1);console.log('压缩前：' + initSize);console.log('压缩后：' + ndata.length);console.log('压缩率：' + ~~(100 * (initSize - ndata.length) / initSize) + "%");tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;return ndata;}

//    图片上传，将base64的图片转成二进制对象，塞进formdata上传function upload(basestr, type, $li) {var text = window.atob(basestr.split(",")[1]);var buffer = new ArrayBuffer(text.length);var ubuffer = new Uint8Array(buffer);var pecent = 0 , loop = null;for (var i = 0; i < text.length; i++) {ubuffer[i] = text.charCodeAt(i);}var Builder = window.WebKitBlobBuilder || window.MozBlobBuilder;var blob;if (Builder) {var builder = new Builder();builder.append(buffer);blob = builder.getBlob(type);} else {blob = new window.Blob([buffer], {type: type});}var xhr = new XMLHttpRequest();var formdata = new FormData();formdata.append('imagefile', blob);xhr.open('post', '/cupload');xhr.onreadystatechange = function () {if (xhr.readyState == 4 && xhr.status == 200) {console.log('上传成功：' + xhr.responseText);clearInterval(loop);//当收到该消息时上传完毕$li.find(".progress span").animate({'width': "100%"}, pecent < 95 ? 200 : 0, function () {$(this).html("上传成功");});$(".pic-list").append('<a href="' + xhr.responseText + '">' + xhr.responseText + '<img src="' + xhr.responseText + '" /></a>')}};//数据发送进度，前50%展示该进度xhr.upload.addEventListener('progress', function (e) {if (loop) return;pecent = ~~(100 * e.loaded / e.total) / 2;$li.find(".progress span").css('width', pecent + "%");if (pecent == 50) {mockProgress();}}, false);//数据后50%用模拟进度function mockProgress() {if (loop) return;loop = setInterval(function () {pecent++;$li.find(".progress span").css('width', pecent + "%");if (pecent == 99) {clearInterval(loop);}}, 100)}xhr.send(formdata);}