Fixing request data param issue. Thanks to mislav for the patch. Fixes #5123.

src/ajax.js

@@ -484,7 +484,7 @@ jQuery.extend({
 
 		// Send the data
 		try {
-			xhr.send( type === "POST" || type === "PUT" || type === "DELETE" ? s.data : null );
+			xhr.send( (type !== "GET" && s.data) || null );
 
 		} catch( sendError ) {
 			jQuery.ajax.handleError( s, xhr, null, e );

test/data/echoData.php

+<?php echo file_get_contents('php://input'); ?>

test/unit/ajax.js

@@ -1163,6 +1163,19 @@ test("data option: evaluate function values (#2806)", function() {
 	})
 });
 
+test("data option: empty bodies for non-GET requests", function() {
+	stop();
+	jQuery.ajax({
+		url: "data/echoData.php",
+		data: undefined,
+		type: "post",
+		success: function(result) {
+			equals( result, "" );
+			start();
+		}
+	})
+});
+
 test("jQuery.ajax - If-Modified-Since support", function() {
 	expect( 3 );