diff --git a/makefile_web b/makefile_web
index 370d9c67..4411489f 100644
--- a/makefile_web
+++ b/makefile_web
@@ -18,7 +18,7 @@ out:
 
 # Both the JS and WASM files are generated by the wasm-bindgen call, so both
 # get to be on the target half of this recipe.
-out/boids.js out/boids_bg.wasm: target/wasm32-unknown-unknown/wasm-release/another-boids-in-rust.wasm | out
+out/boids.js out/boids_bg.wasm &: target/wasm32-unknown-unknown/wasm-release/another-boids-in-rust.wasm | out
 	wasm-bindgen --no-typescript --target web --out-dir ./out/ --out-name boids target/wasm32-unknown-unknown/wasm-release/another-boids-in-rust.wasm
 
 out/index.html: www/index.html