本文介绍了js基于filesaver.js 浏览器导出excel文件，分享给大家，也给自己做个笔记
限制一：不同浏览器对 blob 对象有不同的限制
具体看看下面这个表格（出自filesaver.js）：
| browser | constructs as | filenames | max blob size | dependencies |
|---|---|---|---|---|
| firefox 20+ | blob | yes | 800 mib | none |
| firefox < 20 | data: uri | no | n/a | blob.js |
| chrome | blob | yes | 500 mib | none |
| chrome for android | blob | yes | 500 mib | none |
| edge | blob | yes | ? | none |
| ie 10+ | blob | yes | 600 mib | none |
| opera 15+ | blob | yes | 500 mib | none |
| opera < 15 | data: uri | no | n/a | blob.js |
| safari 6.1+* | blob | no | ? | none |
| safari < 6 | data: uri | no | n/a | blob.js |
限制二：构建完 blob 对象后才会转换成文件
这一点限制对小文件(几十kb)可能没什么影响，但对稍微大一点的文件影响就很大了。试想，用户要下载一个 100mb 的文件，如果他点击了下载按钮之后没看到下载提示的话，他肯定会继续按，等他按了几次之后还没看到下载提示时，他就会抱怨我们的网站，然后离开了。
然而事实上下载的的确确发生了，只是要等到下载完文件之后才能构建 blob 对象，再转化成文件。而且，用户再触发多几次下载就会造成一些资源上的浪费。
因此，如果是要下载大文件的话，还是推荐直接创建一个 <a> 标签拉~
写 html 也好，写 javascript 动态创建也好，用自己喜欢的方式去创建就好了。
filesaver.js
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/* filesaver.js
* a saveas() filesaver implementation.
* 1.3.2
* 2016-06-16 18:25:19
*
* license: mit
* see https://github.com/eligrey/filesaver.js/blob/master/license.md
*/
/*global self */
/*jslint bitwise: true, indent: 4, laxbreak: true, laxcomma: true, smarttabs: true, plusplus: true */
/*! @source http://purl.eligrey.com/github/filesaver.js/blob/master/filesaver.js */
var saveas = saveas || (function(view) {
"use strict";
// ie <10 is explicitly unsupported
if (typeof view === "undefined" || typeof navigator !== "undefined" && /msie [1-9]\./.test(navigator.useragent)) {
return;
}
var
doc = view.document
// only get url when necessary in case blob.js hasn't overridden it yet
, get_url = function() {
return view.url || view.webkiturl || view;
}
, save_link = doc.createelementns("http://www.w3.org/1999/xhtml", "a")
, can_use_save_link = "download" in save_link
, click = function(node) {
var event = new mouseevent("click");
node.dispatchevent(event);
}
, is_safari = /constructor/i.test(view.htmlelement) || view.safari
, is_chrome_ios =/crios\/[\d]+/.test(navigator.useragent)
, throw_outside = function(ex) {
(view.setimmediate || view.settimeout)(function() {
throw ex;
}, 0);
}
, force_saveable_type = "application/octet-stream"
// the blob api is fundamentally broken as there is no "downloadfinished" event to subscribe to
, arbitrary_revoke_timeout = 1000 * 40 // in ms
, revoke = function(file) {
var revoker = function() {
if (typeof file === "string") { // file is an object url
get_url().revokeobjecturl(file);
} else { // file is a file
file.remove();
}
};
settimeout(revoker, arbitrary_revoke_timeout);
}
, dispatch = function(filesaver, event_types, event) {
event_types = [].concat(event_types);
var i = event_types.length;
while (i--) {
var listener = filesaver["on" + event_types[i]];
if (typeof listener === "function") {
try {
listener.call(filesaver, event || filesaver);
} catch (ex) {
throw_outside(ex);
}
}
}
}
, auto_bom = function(blob) {
// prepend bom for utf-8 xml and text/* types (including html)
// note: your browser will automatically convert utf-16 u+feff to ef bb bf
if (/^\s*(?:text\/\s*|application\/xml|\s*\/\s*\+xml)\s*;.*charset\s*=\s*utf-8/i.test(blob.type)) {
return new blob([string.fromcharcode(0xfeff), blob], {type: blob.type});
}
return blob;
}
, filesaver = function(blob, name, no_auto_bom) {
if (!no_auto_bom) {
blob = auto_bom(blob);
}
// first try a.download, then web filesystem, then object urls
var
filesaver = this
, type = blob.type
, force = type === force_saveable_type
, object_url
, dispatch_all = function() {
dispatch(filesaver, "writestart progress write writeend".split(" "));
}
// on any filesys errors revert to saving with object urls
, fs_error = function() {
if ((is_chrome_ios || (force && is_safari)) && view.filereader) {
// safari doesn't allow downloading of blob urls
var reader = new filereader();
reader.onloadend = function() {
var url = is_chrome_ios ? reader.result : reader.result.replace(/^data:[^;]*;/, 'data:attachment/file;');
var popup = view.open(url, '_blank');
if(!popup) view.location.href = url;
url=undefined; // release reference before dispatching
filesaver.readystate = filesaver.done;
dispatch_all();
};
reader.readasdataurl(blob);
filesaver.readystate = filesaver.init;
return;
}
// don't create more object urls than needed
if (!object_url) {
object_url = get_url().createobjecturl(blob);
}
if (force) {
view.location.href = object_url;
} else {
var opened = view.open(object_url, "_blank");
if (!opened) {
// apple does not allow window.open, see https://developer.apple.com/library/safari/documentation/tools/conceptual/safariextensionguide/workingwithwindowsandtabs/workingwithwindowsandtabs.html
view.location.href = object_url;
}
}
filesaver.readystate = filesaver.done;
dispatch_all();
revoke(object_url);
}
;
filesaver.readystate = filesaver.init;
if (can_use_save_link) {
object_url = get_url().createobjecturl(blob);
settimeout(function() {
save_link.href = object_url;
save_link.download = name;
click(save_link);
dispatch_all();
revoke(object_url);
filesaver.readystate = filesaver.done;
});
return;
}
fs_error();
}
, fs_proto = filesaver.prototype
, saveas = function(blob, name, no_auto_bom) {
return new filesaver(blob, name || blob.name || "download", no_auto_bom);
}
;
// ie 10+ (native saveas)
if (typeof navigator !== "undefined" && navigator.mssaveoropenblob) {
return function(blob, name, no_auto_bom) {
name = name || blob.name || "download";
if (!no_auto_bom) {
blob = auto_bom(blob);
}
return navigator.mssaveoropenblob(blob, name);
};
}
fs_proto.abort = function(){};
fs_proto.readystate = fs_proto.init = 0;
fs_proto.writing = 1;
fs_proto.done = 2;
fs_proto.error =
fs_proto.onwritestart =
fs_proto.onprogress =
fs_proto.onwrite =
fs_proto.onabort =
fs_proto.onerror =
fs_proto.onwriteend =
null;
return saveas;
}(
typeof self !== "undefined" && self
|| typeof window !== "undefined" && window
|| this.content
));
// `self` is undefined in firefox for android content script context
// while `this` is nsicontentframemessagemanager
// with an attribute `content` that corresponds to the window
if (typeof module !== "undefined" && module.exports) {
module.exports.saveas = saveas;
} else if ((typeof define !== "undefined" && define !== null) && (define.amd !== null)) {
define("filesaver.js", function() {
return saveas;
});
}
调用方法
function exptoexcel(){
var content = $("#report").html();
var blob = new blob(["hello, world!"], { type: "text/plain;charset=utf-8" });
saveas(blob, "hello world.txt");
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持移动技术网。
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