diff --git a/ajax.js b/ajax.js
index 51ff20a..d5c67a7 100644
--- a/ajax.js
+++ b/ajax.js
@@ -80,9 +80,8 @@ function getJson(url, options={}) {
 
 function postJson(url, data=undefined, options={}) {
 	if (!options.headers) options.headers = {};
-	// This triggers CORS, which is not acceptable
-	//options.headers["Content-Type"] = MIME_JSON;
-	//options.headers["Accept"] = MIME_JSON;
+	options.headers["Content-Type"] = MIME_JSON;
+	options.headers["Accept"] = MIME_JSON;
 
 	return new Promise((resolve, reject) => {
 		let xhr = xhrInitForPromise(resolve, reject, url, "POST", options.headers);