diff --git a/example/web/build-openssl.sh b/example/web/build-openssl.sh
index 5ef3eb2f..5209d0c9 100755
--- a/example/web/build-openssl.sh
+++ b/example/web/build-openssl.sh
@@ -1,18 +1,23 @@
 #!/bin/sh
 
+emconfigure || { echo 'emconfigure not found. Install Emscripten and add emconfigure and emmake to PATH environment variable'; exit 1; }
+
 OPENSSL=OpenSSL_1_1_0j
 if [ ! -f $OPENSSL.tar.gz ]; then
-  echo "Download openssl"
+  echo "Downloading OpenSSL sources..."
   wget https://github.com/openssl/openssl/archive/$OPENSSL.tar.gz
 fi
 rm -rf ./$OPENSSL
+echo "Unpacking OpenSSL sources..."
 tar xzf $OPENSSL.tar.gz || exit 1
 cd openssl-$OPENSSL
 
-emconfigure ./Configure linux-generic32 no-shared
-sed -i bak 's/CROSS_COMPILE=.*/CROSS_COMPILE=/g' Makefile
-emmake make depend -s || exit 1
-emmake make -s || exit 1
+emconfigure ./Configure linux-generic32 no-shared no-dso no-engine no-unit-test no-ui || exit 1
+sed -i.bak 's/CROSS_COMPILE=.*/CROSS_COMPILE=/g' Makefile || exit 1
+sed -i 's/-ldl //g' Makefile || exit 1
+echo "Building OpenSSL..."
+emmake make depend || exit 1
+emmake make -j 4 || exit 1
 
 rm -rf ../build/crypto || exit 1
 mkdir -p ../build/crypto/lib || exit 1
diff --git a/example/web/build-tdlib.sh b/example/web/build-tdlib.sh
index 09f6fb5d..6223d445 100755
--- a/example/web/build-tdlib.sh
+++ b/example/web/build-tdlib.sh
@@ -1,3 +1,5 @@
+emconfigure || { echo 'emconfigure not found. Install Emscripten and add emconfigure to PATH environment variable'; exit 1; }
+
 mkdir -p build/generate
 mkdir -p build/asmjs
 mkdir -p build/wasm
@@ -18,20 +20,19 @@ OPENSSL_OPTIONS="-DOPENSSL_FOUND=1 \
 
 pushd .
 cd build/wasm
-eval emconfigure cmake $TD_ROOT -GNinja $OPENSSL_OPTIONS
+eval emconfigure cmake $TD_ROOT -GNinja $OPENSSL_OPTIONS || exit 1
 popd
 
 pushd .
 cd build/asmjs
-eval emconfigure cmake $TD_ROOT -GNinja -DASMJS=1 $OPENSSL_OPTIONS
+eval emconfigure cmake $TD_ROOT -GNinja -DASMJS=1 $OPENSSL_OPTIONS || exit 1
 popd
 
 pushd .
 cd build/generate
-cmake $TD_ROOT -GNinja
+cmake $TD_ROOT -GNinja || exit 1
 popd
 
-cmake --build build/generate -j --target prepare_cross_compiling 
-cmake --build build/wasm -j --target td_wasm 
-cmake --build build/asmjs -j --target td_asmjs 
-
+cmake --build build/generate -j --target prepare_cross_compiling || exit 1
+cmake --build build/wasm -j --target td_wasm || exit 1
+cmake --build build/asmjs -j --target td_asmjs || exit 1
diff --git a/example/web/build-tdweb.sh b/example/web/build-tdweb.sh
index 34f53347..a899adf3 100755
--- a/example/web/build-tdweb.sh
+++ b/example/web/build-tdweb.sh
@@ -1,4 +1,4 @@
 pushd .
 cd tdweb
-npm install
-npm run build
+npm install || exit 1
+npm run build || exit 1
diff --git a/example/web/copy-tdlib.sh b/example/web/copy-tdlib.sh
index 117cf49a..5e4ca131 100755
--- a/example/web/copy-tdlib.sh
+++ b/example/web/copy-tdlib.sh
@@ -1,4 +1,4 @@
-dest=tdweb/src/prebuilt/release/
-mkdir -p $dest
-cp build/wasm/td_wasm.{js,wasm} $dest
-cp build/asmjs/td_asmjs.js{,.mem} $dest
+DEST=tdweb/src/prebuilt/release/
+mkdir -p $DEST
+cp build/wasm/td_wasm.{js,wasm} $DEST
+cp build/asmjs/td_asmjs.js{,.mem} $DEST