<div class="container">

    <!--文本文件验证-->

    <input type="file" id="file" />

    <h4>选择文件如下:</h4>

    <blockquote></blockquote>

</div>

//读取文本文件实例

var fileBox = document.getElementById('file');

fileBox.onchange = function () {

    showFiles();

}

function showFiles() {

    //获取选择文件的数组

    var fileList = fileBox.files;

    for (var i = 0; i < fileList.length; i++) {

        var file = fileList[i];

        readFile(file);

    }

}

//读取文件内容

function readFile(file) {

    var reader = new FileReader();

    //中文windows系统 txt 文本多数默认编码 gbk

    reader.readAsText(file, 'gbk');

    reader.onprogress = function (e) {

        //默认情况下也是分段读取，

        //默认情况下，每次分段大小不确定，不同浏览器也不相同

        //第一次读取比较小 Google每段：8028160(7.65625mb)   FF每段：786432(768mb)   IE下：4096（4k）

        console.info(e);

    }

    reader.onload = function (e) {

        var result = reader.result;

        console.info(e.loaded);

    }

}

<div class="container">

    <div class="panel panel-default">

        <div class="panel-heading">分段读取文件：</div>

        <div class="panel-body">

            <input  type="file" id="file" />

            <input type="button" id="abort" value="中断" />

            <input type="button" id="containue" value="继续读取文件" />

            <p>

                <label>读取进度：</label><progress id="Progress"  style="width:300px;" value="0" max="100"></progress>

            </p>

            <p id="Percent"></p>

            <p id="Status"></p><hr />

            <blockquote style="word-break:break-all;"></blockquote>

        </div>

    </div>

</div>

var read = {

    //初始化绑定

    init: function () {

        var _this = this;

        _this.status = document.getElementById('Status');

        _this.progress = document.getElementById('Progress');

        _this.percent = document.getElementById('Percent');

        document.getElementById('file').onchange = _this.fileHandler;

        document.getElementById('abort').onclick = _this.abortHandler;

        document.getElementById('containue').onclick = _this.containueHandler;

        _this.loaded = 0;

        //每次读取1M

        _this.step = 3 * 2;

    },

    //当有选中文件时,事件处理

    fileHandler: function (e) {

        //读取文件

        var _this = read;

        //获取上传文件

        var file = _this.file = this.files[0];

        var reader = _this.reader = new FileReader();

        //绑定信息和事件

        _this.total = file.size;
 _this.isabort = false;//标记正在读取还是以已经中止

        reader.onprogress = _this.onProgress;

        reader.onabort = _this.onAbort;

        reader.onerror = _this.onError;

        reader.onload = _this.onLoad;

        //从头读取一块

        _this.readBlob(0);

        $('blockquote').empty();

    },

    //中断 操作

    abortHandler: function (e) {

        var _this = read;

        if (_this.reader) {

            console.log('读取操作操作中止,' + _this.loaded);

            _this.isabort = true;

            _this.reader.abort();

        }

    },

    //继续操作

    containueHandler: function (e) {

        var _this = read;

        _this.isabort = false;

        console.info('继续：' + _this.loaded);

        //继续读取

        _this.readBlob(_this.loaded);

    },

    //读取过程

    onProgress: function (e) {

        var _this = read;

        if (e.lengthComputable == false)

            return;

        _this.loaded += e.loaded;

        //更新进度条

        var value = (_this.loaded / _this.total) * 100;

        _this.percent.innerText = value;

        _this.progress.value = value;

    },

    //中止上传事件

    onAbort: function () {

        var _this = read;

        //console.log('读取操作操作中止,'+_this.loaded);

    },

    //当出现异常时

    onError: function () { },

    //读取成功  结束

    onLoad: function (e) {

        var _this = read;

        var result = _this.reader.result;

        $('blockquote').append(result);

        //判断是否已经读到最后，如果没有继续读取

        if (_this.loaded < _this.total) {
//IE 浏览器下，事件触发速度太快，页面容易出现假死现象，解决方案延缓事件触发

            setTimeout(function () {

                _this.readBlob(_this.loaded);

            }, 10);

            //直接使用在Google，FF没问题

            // _this.readBlob(_this.loaded);

        } else {

            _this.loaded = _this.total;

        }

    },

    readBlob: function (start) {

        var _this = read;
if (_this.isabort)

            return;
var file = _this.file;

        var blob = file.slice(start, start + _this.step);
 _this.reader.readAsText(blob, 'gbk');

    }

};

read.init();

var read = {

    //初始化绑定

    init: function () {

        var _this = this;

        _this.status = document.getElementById('Status');

        _this.progress = document.getElementById('Progress');

        _this.percent = document.getElementById('Percent');

        document.getElementById('file').onchange = _this.fileHandler;

        document.getElementById('abort').onclick = _this.abortHandler;

        _this.loaded = 0;

        //每次读取1M

        //_this.step = 1024 * 1024;

        //_this.step = 1024;

        _this.step = 1024;

        _this.times = 0;

    },

    //当有选中文件时,事件处理

    fileHandler: function (e) {

        //读取文件

        var _this = read;

        //获取上传文件

        var file = _this.file = this.files[0];

        var reader = _this.reader = new FileReader();

        //绑定信息和事件

        _this.total = file.size;

        reader.onloadstart = _this.onLoadStrart;

        reader.onprogress = _this.onProgress;

        reader.onabort = _this.onAbort;

        reader.onerror = _this.onError;

        reader.onload = _this.onLoad;

        //reader.onloadend = _this.onLoadEnd;

        //从头读取一块

        _this.readBlob(0);

        $('blockquote').empty();

    },

    //中断

    abortHandler: function (e) {

        var _this = read;

        if (_this.reader) {

            _this.reader.abort();

        }

    },

    //开始读取文件

    onLoadStrart: function () { },

    //读取过程

    onProgress: function (e) {

        var _this = read;

        //e.loaded 当前读取的数量

        //e.total 读取总量

        _this.loaded += e.loaded;

        //更新进度条

        _this.progress.value = (_this.loaded / _this.total) * 100;

    },

    //中止上传事件

    onAbort: function () { },

    //当出现异常时

    onError: function () { console.log('读取出错'); },

    //读取成功  结束

    onLoad: function (e) {

        var _this = read;

        var reader = _this.reader;

        // console.info(_this.loaded + '---' + _this.total);

        //console.info(reader.result); //ArrayBuffer 数组

        //console.info(reader.result.byteLength); //ArrayBuffer 数组 的长度

        //转换成  Int8Array 类型

        //var b = new Int8Array(reader.result);

        //转换成 Int32Arrary 类型

        var b = new Int32Array(reader.result);

        console.info(b); //ArrayBuffer 数组 的长度

        $('blockquote').append(b.toString());

        //判断是否已经读到最后，如果没有继续读取

        if (_this.loaded < _this.total) {

            _this.readBlob(_this.loaded);

        } else {

            _this.loaded = _this.total;

        }

    },

    //读取结束时 ,每次读取成功结束或调用abord

    onLoadEnd: function (e) {

        //console.log('读取结束');

    },

    readBlob: function (start) {

        var _this = read;

        var blob,

            file = _this.file;

        _this.times += 1;

        console.info('start:' + start);
 blob = file.slice(start, start + _this.step);
 _this.reader.readAsArrayBuffer(blob);

    }

};

read.init();