diff --git a/CMakeLists.txt b/CMakeLists.txt
index d4911732c..790138484 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -93,7 +93,7 @@ if(NOT backend_sdl AND UNIX AND NOT ANDROID AND NOT IOS)
 endif()
 
 #third party build options
-WAGIC_OPTION(BUILD_ZLIB    "build zlib from source"    WIN32 OR APPLE OR EMSCRIPTEN)
+WAGIC_OPTION(BUILD_ZLIB    "build zlib from source"    WIN32 OR APPLE)
 WAGIC_OPTION(BUILD_JPEG    "build jpeg from source"    (WIN32 OR APPLE OR PSP OR ANDROID OR EMSCRIPTEN))
 WAGIC_OPTION(BUILD_PNG     "build png from source"     (WIN32 OR APPLE OR PSP OR ANDROID OR EMSCRIPTEN))
 WAGIC_OPTION(BUILD_UNZIP   "build unzip from source"   ON)
diff --git a/CMakeModules/FindOrBuild.cmake b/CMakeModules/FindOrBuild.cmake
index 1b59810e5..904b9ddaf 100644
--- a/CMakeModules/FindOrBuild.cmake
+++ b/CMakeModules/FindOrBuild.cmake
@@ -101,12 +101,13 @@ macro(FindOrBuildZLIB)
         add_subdirectory(${CMAKE_SOURCE_DIR}/thirdparty/zlib)
         set(ZLIB_INCLUDE_DIRS ${CMAKE_SOURCE_DIR}/thirdparty/zlib ${CMAKE_BINARY_DIR}/thirdparty/zlib)
         set(ZLIB_LIBRARIES zlib)
-	else()
+    else()
         if(WIN32)
             set(ZLIB_ROOT ${CMAKE_SOURCE_DIR}/thirdparty/binary/win)
             find_package(ZLIB)
         else()
-            if(backend_qt_console OR backend_qt_widget)
+            if(backend_qt_console OR backend_qt_widget OR EMSCRIPTEN)
+        	set(ZLIB_INCLUDE_DIRS ${CMAKE_SOURCE_DIR}/thirdparty/zlib)
             else()
                 find_package(ZLIB)
             endif()
diff --git a/platforms/emscripten/configure.cmake b/platforms/emscripten/configure.cmake
index 39d711eb4..4970ff3e8 100644
--- a/platforms/emscripten/configure.cmake
+++ b/platforms/emscripten/configure.cmake
@@ -1,4 +1,4 @@
-set(CMAKE_CXX_FLAGS "-s USE_SDL=2 -s FULL_ES2=1 -std=c++11 -O1 -s ALLOW_MEMORY_GROWTH=1 --preload-file ../../../projects/mtg/bin/Res@/")
+set(CMAKE_CXX_FLAGS "-s USE_SDL=2 -s USE_ZLIB=1 -s FULL_ES2=1 -std=c++11 -O1 -s ALLOW_MEMORY_GROWTH=1 --preload-file ../../../projects/mtg/bin/Res@/")
 #set(CMAKE_CXX_FLAGS "-s USE_SDL=2 -s FULL_ES2=1 -std=c++11 -g4 -s ALLOW_MEMORY_GROWTH=1 --preload-file ../../../projects/mtg/bin/Res@/")
 set(CMAKE_EXECUTABLE_SUFFIX ".html")
 add_definitions(-DLINUX)