diff --git a/lime/_backend/html5/HTML5HTTPRequest.hx b/lime/_backend/html5/HTML5HTTPRequest.hx
index e0544119a..7d1f2c539 100644
--- a/lime/_backend/html5/HTML5HTTPRequest.hx
+++ b/lime/_backend/html5/HTML5HTTPRequest.hx
@@ -109,7 +109,7 @@ class HTML5HTTPRequest {
 			
 		}
 		
-		if (!hasContentType) {
+		if (!hasContentType && parent.contentType != null) {
 			
 			request.setRequestHeader ("Content-Type", parent.contentType);
 			
@@ -381,4 +381,4 @@ class HTML5HTTPRequest {
 	var promise:Dynamic;
 	var uri:String;
 	
-}
\ No newline at end of file
+}