docs.sheetjs.com/docz/static/systemjs/main.js

/* sheetjs (C) 2013-present SheetJS -- http://sheetjs.com */
/*jshint browser:true */
/*global XLSX */
var XLSX = require('xlsx');

var global_wb;

var process_wb = (function() {
	var OUT = document.getElementById('out');
	var HTMLOUT = document.getElementById('htmlout');

	var get_format = (function() {
		var radios = document.getElementsByName( "format" );
		return function() {
			for(var i = 0; i < radios.length; ++i) if(radios[i].checked || radios.length === 1) return radios[i].value;
		};
	})();

	var to_json = function to_json(workbook) {
		var result = {};
		workbook.SheetNames.forEach(function(sheetName) {
			var roa = XLSX.utils.sheet_to_json(workbook.Sheets[sheetName]);
			if(roa.length) result[sheetName] = roa;
		});
		return JSON.stringify(result, 2, 2);
	};

	var to_csv = function to_csv(workbook) {
		var result = [];
		workbook.SheetNames.forEach(function(sheetName) {
			var csv = XLSX.utils.sheet_to_csv(workbook.Sheets[sheetName]);
			if(csv.length){
				result.push("SHEET: " + sheetName);
				result.push("");
				result.push(csv);
			}
		});
		return result.join("\n");
	};

	var to_fmla = function to_fmla(workbook) {
		var result = [];
		workbook.SheetNames.forEach(function(sheetName) {
			var formulae = XLSX.utils.get_formulae(workbook.Sheets[sheetName]);
			if(formulae.length){
				result.push("SHEET: " + sheetName);
				result.push("");
				result.push(formulae.join("\n"));
			}
		});
		return result.join("\n");
	};

	var to_html = function to_html(workbook) {
		HTMLOUT.innerHTML = "";
		workbook.SheetNames.forEach(function(sheetName) {
			var htmlstr = XLSX.write(workbook, {sheet:sheetName, type:'string', bookType:'html'});
			HTMLOUT.innerHTML += htmlstr;
		});
		return "";
	};

	return function process_wb(wb) {
		global_wb = wb;
		var output = "";
		switch(get_format()) {
			case "form": output = to_fmla(wb); break;
			case "html": output = to_html(wb); break;
			case "json": output = to_json(wb); break;
			default: output = to_csv(wb);
		}
		if(OUT.innerText === undefined) OUT.textContent = output;
		else OUT.innerText = output;
		if(typeof console !== 'undefined') console.log("output", new Date());
	};
})();

var setfmt = window.setfmt = function setfmt() { if(global_wb) process_wb(global_wb); };

var b64it = window.b64it = (function() {
	var tarea = document.getElementById('b64data');
	return function b64it() {
		if(typeof console !== 'undefined') console.log("onload", new Date());
		var wb = XLSX.read(tarea.value, {type:'base64', WTF:false});
		process_wb(wb);
	};
})();

var do_file = (function() {
	return function do_file(files) {
		var f = files[0];
		var reader = new FileReader();
		reader.onload = function(e) {
			if(typeof console !== 'undefined') console.log("onload", new Date());
			var data = e.target.result;
			data = new Uint8Array(data);
			process_wb(XLSX.read(data, {type: 'array'}));
		};
		reader.readAsArrayBuffer(f);
	};
})();

(function() {
	var drop = document.getElementById('drop');
	if(!drop.addEventListener) return;

	function handleDrop(e) {
		e.stopPropagation();
		e.preventDefault();
		do_file(e.dataTransfer.files);
	}

	function handleDragover(e) {
		e.stopPropagation();
		e.preventDefault();
		e.dataTransfer.dropEffect = 'copy';
	}

	drop.addEventListener('dragenter', handleDragover, false);
	drop.addEventListener('dragover', handleDragover, false);
	drop.addEventListener('drop', handleDrop, false);
})();

(function() {
	var xlf = document.getElementById('xlf');
	if(!xlf.addEventListener) return;
	function handleFile(e) { do_file(e.target.files); }
	xlf.addEventListener('change', handleFile, false);
})();