js の Blob オブジェクト タイプの詳細な紹介

var blob = new Blob(array[optional], options[optional]);

MimeType mimeType = MimeType.toEnum(file.getContentType());）。

Uncaught TypeError: Failed to construct ‘Blob': The 1st argument is neither an array, nor does it have indexed properties.

window.onload = function() { var arg = {hello: "2016"}; var blob = new Blob([JSON.stringify(arg, null, "\t")], {type: "application/json"}); console.log(blob.type);//application/json console.log(blob.size);//20 }

Blob.slice([start, [end, [content-type]]])

function sliceBlob(blob, start, end, type) { type = type || blob.type; if (blob.mozSlice) { return blob.mozSlice(start, end, type); } else if (blob.webkitSlice) { return blob.webkitSlice(start, end type); } else { throw new Error("This doesn't work!"); } }

var input = document.createElement("input"); input.type = "file"; input.accept = "image/*"; input.multiple = true; input.style.display = "none"; document.body.appendChild(input); var fileSelect = document.createElement("a"); fileSelect.href = "#"; fileSelect.appendChild(document.createTextNode("Choose files")); document.body.appendChild(fileSelect); var imgList = document.createElement("div"); imgList.innerHTML = "
No file Selected!
" document.body.appendChild(imgList); input.addEventListener("change", function(e) { var files = this.files; if(!files.length) { return; } imgList.innerHTML = ""; var list = document.createElement("ul"); imgList.appendChild(list); for(var i = 0; i < files.length; i++) { var li = document.createElement("li"); list.appendChild(li); var img = document.createElement("img"); img.src = window.URL.createObjectURL(files[i]); img.height = 60; img.width = 60; img.onload = function() { window.URL.revokeObjectURL(this.src); } li.appendChild(img); var info = document.createElement("span"); info.innerHTML = files[i].name + ":" + files[i].size + " bytes"; li.appendChild(info); } }, false); fileSelect.addEventListener("click", function(e) { input.click(); e.preventDefault(); }, false);