Ajax: Support binary data (including FormData)

Two changes have been applied:
* prefilters are now applied before data is converted to a string;
  this allows prefilters to disable such a conversion
* a prefilter for binary data is added; it disables data conversion
  for non-string non-plain-object `data`; for `FormData` bodies, it
  removes manually-set `Content-Type` header - this is required
  as browsers need to append their own boundary to the header

Ref gh-4150
Closes gh-5197

1 files changed, 3 insertions, 3 deletions

diff --git a/src/ajax.js b/src/ajax.js
index 36a9c9b57..db4e30195 100644
--- a/src/ajax.js
+++ b/src/ajax.js
@@ -562,14 +562,14 @@ jQuery.extend( {
 			}
 		}
 
+		// Apply prefilters
+		inspectPrefiltersOrTransports( prefilters, s, options, jqXHR );
+
 		// Convert data if not already a string
 		if ( s.data && s.processData && typeof s.data !== "string" ) {
 			s.data = jQuery.param( s.data, s.traditional );
 		}
 
-		// Apply prefilters
-		inspectPrefiltersOrTransports( prefilters, s, options, jqXHR );
-
 		// If request was aborted inside a prefilter, stop there
 		if ( completed ) {
 			return jqXHR;