diff --git a/build-wasm.cmd b/build-wasm.cmd
index 0da923d..55082c5 100644
--- a/build-wasm.cmd
+++ b/build-wasm.cmd
@@ -11,6 +11,18 @@ if not exist build\emsdk (
   git clone https://github.com/emscripten-core/emsdk.git build\emsdk
 )
 
+rem Check for Ninja binary
+pushd build\wasm
+if not exist "ninja.exe" (
+  rem Install Ninja
+  curl -L https://github.com/ninja-build/ninja/releases/download/v1.11.1/ninja-win.zip -o ninja.zip
+  tar -xzvf ninja.zip
+  del ninja.zip
+)
+rem must setup PATH for ninja first to avoid conflict with emsdk_env.bat
+set PATH="%PATH%;%cd%"
+popd
+
 pushd build\emsdk
 rem git pull
 call emsdk.bat install 3.0.0
@@ -21,13 +33,6 @@ popd
 pushd build\wasm
 
 call emcmake cmake -DCMAKE_BUILD_TYPE=%BUILD_TYPE% ..\..
-rem Check if Ninja binary exists
-if not exist "ninja.exe" (
-  rem Install Ninja
-  curl -L https://github.com/ninja-build/ninja/releases/download/v1.11.1/ninja-win.zip -o ninja.zip
-  unzip ninja.zip
-  del ninja.zip
-)
 ninja.exe -f build.ninja -j 3
 
 set "TARGET_FILES=QmcLegacy.js QmcWasm.js QmcWasm.wasm QmcWasmBundle.js %CURR_DIR%\LICENSE.txt"