PHP和Ajax文件上传-无法通过$ _FILES获得tmp_name

Question

I'm trying to upload a file using Ajax, but I'm having troubles handling the file... For test purposes I've build a simple code that looks like this:

JS:

xmlhttp=new XMLHttpRequest();
xmlhttp.open("POST",document.getElementById('upload').action,true);
xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
var cmdStr="q="+str;
xmlhttp.send(cmdStr);

document.getElementById("ResponseDiv").innerHTML=xmlhttp.responseText;

PHP:

$q=$_POST["q"];
echo $q;

It works fine and xmlhttp.responseText prints [object File] .

My problem, however, is that I need to get the temporary file name with $_FILES["q"]['tmp_name'] . To do so I have changed the code to the following:

JS:

xmlhttp=new XMLHttpRequest();
xmlhttp.open("POST",document.getElementById('upload').action,true);
xmlhttp.setRequestHeader("enctype","multipart/form-data");
var cmdStr="q="+str;
xmlhttp.send(cmdStr);

document.getElementById("ResponseDiv").innerHTML=xmlhttp.responseText;

PHP:

$q=$_FILES["q"]["tmp_name"];
echo $q;

Problem is that now with xmlhttp.responseText I don't get anything. Anyone knows what I'm doing wrong?

Answer 1

Check out this answer for making file uploads with AJAX. It is possible, but not compatible in all browsers.

jQuery Upload Progress and AJAX file upload

--

Alternatively, if you want on the fly uploads, there is a cool library you can get called 'Uploadify'. It's a flash/jquery (or HTML5 now) rig that allows you to upload files on the fly. In the flash version, last time I used it... you can add in callback functions to make it do essentially anything you want.

Some clever javascript could make this work for you.

http://www.uploadify.com/

Answer 2

AJAX doesn't do file uploads. It's not designed for that. The standard workaround is to have the JS code build a hidden iframe and do a standard POST-type upload in that. As such, if you try doing echo $_FILES['q']['error'] , you'd probably have gotten 4 for "no file".