1、工具的用途：用HTML5 file api读取文件的MD5码。MD5码在文件的唯一性识别上有很重要的应用，业内常用MD5进行文件识别、文件秒传、文件安全性检查等；
2、适用性：IE、Chrome皆兼容；
3、缺陷：当上传大文件时，需要较长的时间才能扫描出MD5码；
4、关于引用：其中引用了js文件（spark-md5.js）
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <title>HTML5 read files hash</title> <meta name="author" content="Mofei"> <meta name="viewport" content="width=device-width; initial-scale=1.0;"> <script src="spark-md5.js" type="text/javascript"></script> </head> <body> <div> <header> <h1>HTML5 read files hash</h1> </header> <div> <input type="file" id="file"> <div id="box"></div> </div> <footer> <p>© Copyright by Percy(<a href="http://www.cnblogs.com/Percy_Lee/">www.cnblogs.com/Percy_Lee</a>)</p> </footer> </div> <script type="text/javascript"> document.getElementById("file").addEventListener("change", function () { var fileReader = new FileReader(), box = document.getElementById('box'), blobSlice = File.prototype.mozSlice || File.prototype.webkitSlice || File.prototype.slice, file = document.getElementById("file").files[0], chunkSize = 2097152, chunks = Math.ceil(file.size / chunkSize), currentChunk = 0, bs = fileReader.readAsBinaryString, spark = bs ? new SparkMD5() : new SparkMD5.ArrayBuffer(); fileReader.onload = function (ee) { spark.append(ee.target.result); currentChunk++; if (currentChunk < chunks) { loadNext(); } else { box.innerText = 'MD5: ' + spark.end(); } } function loadNext() { var start = currentChunk * chunkSize, end = start + chunkSize >= file.size ? file.size : start + chunkSize; if (bs) fileReader.readAsBinaryString(blobSlice.call(file, start, end)); else fileReader.readAsArrayBuffer(blobSlice.call(file, start, end)); } loadNext(); }); </script> </body> </html>