local_io.js

(function(root, factory) {
    if (typeof exports === "object" && typeof module === "object")
        module.exports = factory();
    else if (typeof define === "function" && define.amd)
        define([], factory);
    else if (typeof define === "function" && define.cmd)
        define(function(require, exports, module) {
            module.exports = factory();
        });
    else root.MyFileIO = factory();
})(this, function() {
    "use strict";

    function loadString(arg, onReady) {
        var file = (typeof arg === 'string') ? arg : (arg.currentTarget ? arg.target : arg);
        var reader;
        // HTML5
        if (window.FileReader) {
            reader = new FileReader();
            reader.onload = function() {
                onReady(this.result);
            };
            reader.readAsText((typeof file === 'string') ? file : file.files[0]);
        }
        // For IE
        else if (typeof window.ActiveXObject !== 'undefined') {
            reader = new ActiveXObject("Scripting.FileSystemObject");
            if (!reader.fileExists((typeof file === 'string') ? file : file.value))
                onReady(null);
            reader = reader.OpenTextFile((typeof file === 'string') ? file : file.value, 1, false, -2);
            var content = file.readAll();
            reader.close();
            onReady(content);
        }
        // FireFox
        else if (document.implementation && document.implementation.createDocument) {
            reader = document.implementation.createDocument("", "", null);
            reader.async = false;
            reader.load((typeof file === 'string') ? file : file.value);
            onReady(reader.xml);
        } else {
            alert('error');
        }
    }

    function saveString(arg, text) {
        var file = (typeof arg === 'string') ? arg : (arg.currentTarget ? arg.target : arg);
        var writer;
        // HTML5
        if (window.FileWriter) {
            writer = new FileWriter((typeof file === 'string') ? file : file.files[0]);
            writer.write(text);
        }
        // For IE
        else if (typeof window.ActiveXObject !== 'undefined') {
            writer = new ActiveXObject("Scripting.FileSystemObject");
            writer = writer.CreateTextFile((typeof file === 'string') ? file : file.value, true, true);
            writer.Write(text);
            writer.close();
        }
    }

    function loadBinaryString(arg, onReady) {
        var file = (typeof arg === 'string') ? arg : (arg.currentTarget ? arg.target : arg);
        var reader;
        // HTML5
        if (window.FileReader) {
            reader = new FileReader();
            reader.onload = function() {
                onReady(this.result);
            };
            reader.readAsBinaryString((typeof file === 'string') ? file : file.files[0]);
        }
        // For IE
        else if (typeof window.ActiveXObject !== 'undefined') {
            reader = new ActiveXObject("ADODB.Stream");
            reader.Type = 1;
            reader.Open();
            reader.LoadFromFile((typeof file === 'string') ? file : file.value);
            reader.Position = 0;
            var what = reader.Read();
            reader.Close();
            onReady(what);
        }
    }
    return {
        loadString: loadString,
        saveString: saveString,
        loadBinaryString: loadBinaryString
    };
});