submitting a form to the server as json - sencha-touch

Question

I am trying to submit a form to the server with the params in JSON.
form.submit({
url:'JSONSaveEntry',
method:'POST'
});
but it sends everything as form-www-urlencoded.
I already checked that no field has isFile set to true (but then, it would send as multipart-formdata) and that standardSubmit is false.
I also tried to use
Ext.Ajax.request({
url:'JSONSaveEntry',
method:'POST',
params:form.getValues()
});
and
Ext.Ajax.request({
url:'JSONSaveEntry',
method:'POST',
params:Ext.encode(form.getValues())
});
Every submission is done as form-www-urlencoded, although the docs clearly state "Performs a Ajax-based submission of form values (if standardSubmit is false)". But then, this sentence is already proven wrong because whenever a file field is in the form, the form is submitted as multipart.
So, does anyone know how I can get the form submitted as JSON?
Possibility 2: I know that it works if I submit a model via model.save(), but how would I create a model from a form on-the-fly (without hardcoding the fields twice)?

Answer 1

I think below would solve your purpose.
Ext.Ajax.request({
url:'JSONSaveEntry',
method:'POST',
headers: { 'Content-Type': 'application/json' },
jsonData : JSON.stringify(form.getValues()),
success : function(response){ console.log("response from server")},
failure : function(error){console.log(error)}
});