抓住自己最有兴趣的东西，由浅入深，循序渐进地学……
前端index.html代码：
<!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="utf-8" />
<title>Pure HTML5 file upload | Script Tutorials</title>
<link href="css/main.css" rel="stylesheet" type="text/css" />
<script src="js/script.js"></script>
</head>
<body>
<header>
<h2>Pure HTML5 file upload</h2>
<a href="http://www.script-tutorials.com/pure-html5-file-upload/" class="stuts">Back to original tutorial on <span>Script Tutorials</span></a>
</header>
<div class="container">
<div class="contr"><h2>You can select the file (image) and click Upload button</h2></div>
<div class="upload_form_cont">
<form id="upload_form" enctype="multipart/form-data" method="post" action="upload.php">
<div>
<div><label for="image_file">Please select image file</label></div>
<div><input type="file" name="image_file" id="image_file" onchange="fileSelected();" /></div>
</div>
<div>
<input type="button" value="Upload" onclick="startUploading()" />
</div>
<div id="fileinfo">
<div id="filename"></div>
<div id="filesize"></div>
<div id="filetype"></div>
<div id="filedim"></div>
</div>
<div id="error">You should select valid image files only!</div>
<div id="error2">An error occurred while uploading the file</div>
<div id="abort">The upload has been canceled by the user or the browser dropped the connection</div>
<div id="warnsize">Your file is very big. We can't accept it. Please select more small file</div>
<div id="progress_info">
<div id="progress"></div>
<div id="progress_percent"> </div>
<div class="clear_both"></div>
<div>
<div id="speed"> </div>
<div id="remaining"> </div>
<div id="b_transfered"> </div>
<div class="clear_both"></div>
</div>
<div id="upload_response"></div>
</div>
</form>
<img id="preview" />
</div>
</div>
</body>
</html>
后端php代码：
<?php
function bytesToSize1024($bytes, $precision = 2) {
$unit = array('B','KB','MB');
return @round($bytes / pow(1024, ($i = floor(log($bytes, 1024)))), $precision).' '.$unit[$i];
}
$sFileName = $_FILES['image_file']['name'];
$sFileType = $_FILES['image_file']['type'];
$sFileSize = bytesToSize1024($_FILES['image_file']['size'], 1);
echo <<<EOF
<p>Your file: {$sFileName} has been successfully received.</p>
<p>Type: {$sFileType}</p>
<p>Size: {$sFileSize}</p>
EOF;
js和css文件在包里。整个示例程序打包从这里下载：html5+php上传示例源代码
