dom: fix HttpRes.contentBuf and beef up documentation

src/dom/es/HttpReqPeer.js

@@ -104,7 +104,7 @@ class HttpReqPeer extends sys.Obj {
     if (isText)
       res.content(xhr.responseText);
     else if (xhr.responseType == "arraybuffer")
-      res.contentBuf(sys.MemBuf.__makeBytes(res.content));
+      res.contentBuf(sys.MemBuf.__makeBytes(xhr.response));
 
     const all = xhr.getAllResponseHeaders().split("\n");
     for (let i=0; i<all.length; i++)
@@ -152,4 +152,5 @@ class HttpReqPeer extends sys.Obj {
     // send POST request
     self.send("POST", data, f);
   }
-}
+}
+

src/dom/fan/HttpReq.fan

@@ -33,8 +33,9 @@ class HttpReq
 
   ** The type of data contained in the response. It also lets the
   ** author change the response type. If an empty string is set as
-  ** the value, the default value of '"text"' is used.
-  @NoDoc Str resType := ""
+  ** the value, the default value of '"text"' is used.  Set this
+  ** field to "arraybuffer" to access response as Buf.
+  Str resType := ""
 
   **
   ** Indicates whether or not cross-site 'Access-Control' requests
@@ -101,3 +102,4 @@ class HttpReq
   **
   native Void postFormMultipart(Str:Obj form, |HttpRes res| c)
 }
+

src/dom/fan/HttpRes.fan

@@ -25,10 +25,11 @@ class HttpRes
   Str:Str headers := Str:Str[:] { it.caseInsensitive = true }
 
   ** The text content of the response when the XMLHttpRequest
-  ** 'responseType' is 'text'.
+  ** `HttpReq.resType` is "text"
   Str content := ""
 
   ** The binary content of the response when the XMLHttpRequest
-  ** 'responseType' is 'arraybuffer'
+  ** `HttpReq.resType` is "arraybuffer"
   Buf contentBuf := Buf(0)
-}
+}
+