Client-side exception when a Zone containing a Form with an Upload component is re-rendered

I have run into an issue with javascript that runs after the zone which contains an upload component is re rendered. The code would look like this

<t:zone t:id="zone">
<t:form t:id="form">
<input t:type="upload" t:value="value" />
</t:form>
</t:zone>

once this is rendered the javascript would send an error TypeError: Cannot set property 'enctype' of undefined http://localhost:8080/assets/0.55-SNAPSHOT/jquery/tapestry-jquery.js:904

what happens is that once the ajax starts to work the Upload component (Upload.java) sends the code that is to be executed

Tapestry.Initializer.injectedUpload = function(element)
{
var form = $(element).form;

form.enctype = "multipart/form-data";
form.encoding = "multipart/form-data";
}

$(element).form returns null for partial updates.

the code for that can be found https://github.com/apache/tapestry5/blob/trunk/tapestry-upload/src/main/resources/org/apache/tapestry5/upload/components/upload.js

the solution that worked for me is

Tapestry.Initializer.injectedUpload = function(element)
{
var form = $(element).form;

if(form)

{ form.enctype = "multipart/form-data"; form.encoding = "multipart/form-data"; }

}

two more thing that are maybe worth to mention is that I was using tapestry-jquery plugin (but since this code comes from the tapestry core and it has nothing to do with jquery I think that it is irrelevant). the second thing is that the reason this error shows up is because what is send from the ajax (along with the code that is to be executed in javascript) is the list of components (in my case it was a list of 6) 5 textfields and 1 upload. All of them apart from upload where return as objects the upload was returned from ajax was a string which is why the

var form = $(element).form;

is not working and the solution about works

One other thing to mention is that this error does not affect java code only the javascript since an error is thrown so javascript stops to work on the page

the discussion on the forum can be found here http://tapestry.1045711.n5.nabble.com/Zone-refresh-image-uplaod-td5631622.html#a5634387