diff --git a/README.md b/README.md
index e73c278..2ef5d7e 100644
--- a/README.md
+++ b/README.md
@@ -52,10 +52,11 @@ git clone https://github.com/ading2210/libcurl.js --recursive
 cd libcurl.js/client
 ./build.sh
 ```
-Make sure you have emscripten v3.1.6, git, and the various C build tools installed. The only OS supported for building libcurl.js is Linux. On Debian-based systems, you can run the following command to install all the dependencies:
+Make sure you have emscripten, git, and the various C build tools installed. The only OS supported for building libcurl.js is Linux. On Debian-based systems, you can run the following command to install all the dependencies:
 ```
 sudo apt install make cmake emscripten autoconf automake libtool pkg-config wget xxd jq
 ```
+Emscripten versions 3.1.6 and 3.1.72 have been tested and known to work. 
 
 The build script will generate `client/out/libcurl.js` as well as `client/out/libcurl.mjs`, which is an ES6 module. You can supply the following arguments to the build script to control the build:
 - `release` - Use all optimizations.
diff --git a/client/build.sh b/client/build.sh
index a6b5dc1..0cda2a6 100755
--- a/client/build.sh
+++ b/client/build.sh
@@ -18,6 +18,16 @@ MODULE_FILE="$OUT_DIR/emscripten_compiled.js"
 COMPILED_FILE="$OUT_DIR/emscripten_compiled.wasm"
 WASM_FILE="$OUT_DIR/libcurl.wasm"
 
+#check last used emscripten version
+CURRENT_EMCC_VER="$(emcc --version)"
+LAST_EMCC_VER="$(cat "$BUILD_DIR/emcc_version.txt" || emcc --version)"
+if [ ! "$CURRENT_EMCC_VER" = "$LAST_EMCC_VER" ]; then
+  echo "triggering a full rebuild since we're on a different emcc version"
+  rm -rf "$BUILD_DIR"
+  mkdir -p "$BUILD_DIR"
+fi
+emcc --version > "$BUILD_DIR/emcc_version.txt"
+
 #read exported functions
 EXPORTED_FUNCS=""
 for func in $(cat exported_funcs.txt); do
diff --git a/client/fragments/force_wsproxy.js b/client/fragments/force_wsproxy.js
index 81554bc..d65e701 100644
--- a/client/fragments/force_wsproxy.js
+++ b/client/fragments/force_wsproxy.js
@@ -3,4 +3,12 @@ var ?opts ?= ?undefined;
 */
 var parts = addr.split("/");
 if (!url.endsWith("/")) url += "/";
-url += parts[0] + ":" + port;
\ No newline at end of file
+url += parts[0] + ":" + port;
+
+/* REPLACE
+url ?= ?SOCKFS\.websocketArgs\[['"]url['"]\];
+*/
+var parts = addr.split("/");
+url = Module.websocket.url;
+if (!url.endsWith("/")) url += "/";
+url += parts[0] + ":" + port;
diff --git a/client/fragments/load_later.js b/client/fragments/load_later.js
index 2fb25b4..183a7c6 100644
--- a/client/fragments/load_later.js
+++ b/client/fragments/load_later.js
@@ -1,16 +1,16 @@
 /* REPLACE
 var asm ?= ?createWasm\(\);
 */
-if (isDataURI(wasmBinaryFile)) var asm = createWasm();
+if (wasmBinaryFile && isDataURI(wasmBinaryFile)) var asm = createWasm();
 else var asm = null;
 
 /* REPLACE
 var wasmExports ?= ?createWasm\(\);
 */
-if (isDataURI(wasmBinaryFile)) var wasmExports = createWasm();
+if (wasmBinaryFile && isDataURI(wasmBinaryFile)) var wasmExports = createWasm();
 else var wasmExports = null;
 
 /* REPLACE
 run\(\);\n\n
 */
-if (isDataURI(wasmBinaryFile)) run();
\ No newline at end of file
+if (wasmBinaryFile && isDataURI(wasmBinaryFile)) run();
\ No newline at end of file
diff --git a/client/fragments/silence_socket.js b/client/fragments/silence_socket.js
index de7bf00..1eac179 100644
--- a/client/fragments/silence_socket.js
+++ b/client/fragments/silence_socket.js
@@ -2,8 +2,3 @@
 err\("__syscall_getsockname " ?\+ ?fd\);
 */
 
-
-/* INSERT
-function _emscripten_console_error\(str\) ?{
-*/
-if (UTF8ToString(str).endsWith("__syscall_setsockopt\\n")) return;
\ No newline at end of file
diff --git a/client/javascript/main.js b/client/javascript/main.js
index bc8d50e..c8a0bf0 100644
--- a/client/javascript/main.js
+++ b/client/javascript/main.js
@@ -45,6 +45,8 @@ function set_websocket_url(url) {
   websocket_url = url;
   if (typeof Module.websocket === "undefined") 
     Module.websocket = {};
+  if (typeof SOCKFS.websocketArgs !== "undefined") 
+    SOCKFS.websocketArgs.url = url;
   Module.websocket.url = url;
   if (!main_session && wasm_ready) {
     setup_main_session();
@@ -101,7 +103,7 @@ function load_wasm(url) {
   if (wasm_ready) return;
 
   //skip this if we are running in single file mode
-  if (!isDataURI(wasmBinaryFile)) {
+  if (!wasmBinaryFile || !isDataURI(wasmBinaryFile)) {
     wasmBinaryFile = url;
     createWasm();
     run();  
diff --git a/client/libcurl/request.c b/client/libcurl/request.c
index b9e6f51..2b1a56b 100644
--- a/client/libcurl/request.c
+++ b/client/libcurl/request.c
@@ -46,6 +46,9 @@ CURL* create_request(const char* url, int request_id, DataCallback data_callback
   curl_easy_setopt(http_handle, CURLOPT_CAINFO_BLOB, cacert_blob);
   curl_easy_setopt(http_handle, CURLOPT_BUFFERSIZE, 512*1024);
 
+  //emscripten doesn't support tcp nodelay anyways
+  curl_easy_setopt(http_handle, CURLOPT_TCP_NODELAY, 0L);
+
   //callbacks to pass the response data back to js
   curl_easy_setopt(http_handle, CURLOPT_WRITEFUNCTION, &write_function);
   curl_easy_setopt(http_handle, CURLOPT_WRITEDATA, request_info);