您不能像发送 HTML 元素的值那样发送文件。文件上传有两种方法，我使用成功的一种是使用名为“AjaxUploader”的第三方功能的 AJAX 方法。您可以通过 GitHub下载。完成后，将 ajaxuploader.js 文件添加到您的“js”文件夹（或您放置所有脚本文件的任何位置）中，将该文件包含在您必须使用上传器的 HTML 页面中。现在，上传很简单，如下所示。
HTML：
<input type="file" name="transcriptUploader" id="transcriptUploader" value="Upload" />
jQuery（您需要在页面中包含 jQuery 文件）：
new AjaxUpload('transcriptUploader', {
action: "page_to_handle_upload.php", // You need to have either a separate PHP page to handle upload or a separate function. Link to either one of them here
name: 'file',
onSubmit: function(file, extension) {
// This function will execute once a user has submitted the uploaded file. You can use it to display a loader or a message that the file is being uploaded.
},
onComplete: function(file, response) {
// This function will execute once your file has been uploaded successfully.
var data = $.parseJSON(response); // Parsing the returning response from JSON.
if(data.error == 0)
{
// If the file uploaded successfully.
}
else if(data.error == "size"){
// If the response object sent 'size' as the error. It means the file size exceeds the size specified in the code.
}
else if(data.error == "type"){
// If the response object sent 'type' as the error. It means the file type is not of that specified in the code (in your case, pdf).
}
else{
// In case the file didn't upload successfully or the code didn't return a usual error code. It is still an error so you need to deal with it appropriately.
}
}
});
您的后端 PHP 代码将完成所有繁重的工作（上传文件、检查扩展名、移动文件等）：
if(isset($_FILES)) // Checking if a file is posted.
{
if ($_FILES['file']['error'] == 0) //Checking if file array contain 0 as an error. It means AJAX had no error posting the file.
{
$response = array(); // Initializing a new array.
$allowedExts = array("pdf"); // Allowable file format.
$filename = stripslashes($_FILES['file']['name']); // Storing file name.
//$extension = strtolower(self::_getExtension($filename)); // Fetching file extension.
// Code block to extract file extension and storing it in a variable called $extraction.
$i = strrpos($str, ".");
if (!$i)
{
$extension = "";
}
$l = strlen($str) - $i;
$extension = strlower(substr($str, $i + 1, $l));
$size = $_FILES['file']['size']; // Storing file size (in bytes).
$fileNameAfterUpload = md5((time() + microtime())) . '.' . $extension; // Concatinating file name and extension.
$baseSystemPath = "/var/www/<your_folder_name>/uploaded_transcripts/" // Path on which the file will be uploaded. Need to be relative web path.
$maxSize = 10*10*1024; // Storing file size. Be advised the file size is in bytes, so this calculation means max file size will be 10 MB.
$webPath = "uploaded_transcripts/". $filename; // Creating web path by concatinating base web path (the folder in which you'd be uploading the pdf files to) with file name.
if (in_array($extension, $allowedExts)) // Checking if file contains allowabale extensions.
{
if($size <= $maxSize) // Checking if the size of file is less than and equal to the maximum allowable upload size.
{
$moved = move_uploaded_file($_FILES['file']['tmp_name'], $webPath); // Moving the file to the path specified in $webPath variable.
if($moved == true)
{
$response['error'] = 0; // If moved successfully, storing 0 in the response array.
$response['path'] = $webPath; // Storing web path as path in the response array.
$response['filename'] = $filename; // Storing file name in the response array.
}
else
{
$response['error'] = 'internal'; // If move isn't successfull, return 'internal' to AJAX.
}
}
else
{
$response['error'] = 'size'; // If file size is too small or large, return 'size' to AJAX.
}
}
else
{
$response['error'] = 'type'; // If file type is not that of defined, return 'type' to AJAX.
}
echo json_encode($response); // Returning the response in JSON format to AJAX.
}
}
如果您需要进一步的帮助，请告诉我。PS：如果有效，请不要忘记将其标记为答案。