jQuery 上传进度和 AJAX 文件上传

如今，使用AJAX上传文件实际上是可能的.是的，是AJAX，而不是像swf或java这样的蹩脚AJAX爱好者.

This example might help you out: https://webblocks.nl/tests/ajax/file-drag-drop.html

(It also includes the drag/drop interface but that's easily ignored.)

Basically what it comes down to is this:

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

<script>
document.getElementById('files').addEventListener('change', function(e) {
    var file = this.files[0];
    var xhr = new XMLHttpRequest();
    (xhr.upload || xhr).addEventListener('progress', function(e) {
        var done = e.position || e.loaded
        var total = e.totalSize || e.total;
        console.log('xhr progress: ' + Math.round(done/total*100) + '%');
    });
    xhr.addEventListener('load', function(e) {
        console.log('xhr upload complete', e, this.responseText);
    });
    xhr.open('post', '/URL-HERE', true);
    xhr.send(file);
});
</script>

(演示:http://jsfiddle.net/rudiedirkx/jzxmro8r/)

所以基本上归结起来就是=)

xhr.send(file);

其中file是Blob:http://www.w3.org/TR/FileAPI/的类型

Another (better IMO) way is to use FormData. This allows you to 1) name a file, like in a form and 2) send other stuff (files too), like in a form.

var fd = new FormData;
fd.append('photo1', file);
fd.append('photo2', file2);
fd.append('other_data', 'foo bar');
xhr.send(fd);

FormData使服务器代码更干净、更向后兼容(因为现在请求的格式与普通表单完全相同).

All of it is not experimental, but very modern. Chrome 8+ and Firefox 4+ know what to do, but I don't know about any others.

以下是我在PHP中处理请求(每个请求一个图像)的方式:

if ( isset($_FILES['file']) ) {
    $filename = basename($_FILES['file']['name']);
    $error = true;

    // Only upload if on my home win dev machine
    if ( isset($_SERVER['WINDIR']) ) {
        $path = 'uploads/'.$filename;
        $error = !move_uploaded_file($_FILES['file']['tmp_name'], $path);
    }

    $rsp = array(
        'error' => $error, // Used in JS
        'filename' => $filename,
        'filepath' => '/tests/uploads/' . $filename, // Web accessible
    );
    echo json_encode($rsp);
    exit;
}