diff --git a/emsdk b/emsdk
index 308b59e..f43f2da 100644
--- a/emsdk
+++ b/emsdk
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 
-import sys, optparse, subprocess, urllib2, os, os.path, errno, zipfile, string, json, platform, shutil, tarfile
+import sys, optparse, subprocess, urllib2, os, os.path, errno, zipfile, string, json, platform, shutil, tarfile, urlparse
 
 # EMSDK_DEV is a developer mode flag, which, if true, the SDK is downloaded from a 'staging' online source,
 # instead of the public source. New releases are first deployed to the staging source for testing, before 
@@ -238,7 +238,7 @@ def git_clone_checkout_and_pull(url, dstpath, branch):
   return success
 
 def download_and_unzip(zipfile, dst):
-  success = download_file(emsdk_master_server + zipfile, 'zips/')
+  success = download_file(urlparse.urljoin(emsdk_master_server, zipfile), 'zips/')
   if not success:
     return False
   if zipfile.endswith('.zip'):
@@ -496,7 +496,7 @@ class Tool:
       elif url.endswith('zip') or url.endswith('.tar') or url.endswith('.gz'):
         success = download_and_unzip(url, self.installation_path())
       else:
-        success = download_file(emsdk_master_server + self.download_url(), self.installation_path())
+        success = download_file(urlparse.urljoin(emsdk_master_server, self.download_url()), self.installation_path())
       if not success:
         print "Installation failed!"
         return False
@@ -566,16 +566,16 @@ def find_latest_sdk():
   return sdks[-1] # Newest SDK is always at the end of the list.
 
 def update_emsdk():
-  download_text_file(emsdk_master_server + 'emsdk_manifest.json', emsdk_path(), download_even_if_exists=True)
+  download_text_file(urlparse.urljoin(emsdk_master_server, 'emsdk_manifest.json'), emsdk_path(), download_even_if_exists=True)
   if not EMSDK_DEV:
-    download_text_file(emsdk_master_server + 'emsdk', emsdk_path(), download_even_if_exists=True)
-  download_text_file(emsdk_master_server + 'README.md', emsdk_path(), download_even_if_exists=True)
+    download_text_file(urlparse.urljoin(emsdk_master_server, 'emsdk'), emsdk_path(), download_even_if_exists=True)
+  download_text_file(urlparse.urljoin(emsdk_master_server, 'README.md'), emsdk_path(), download_even_if_exists=True)
   if WINDOWS:
-    download_text_file(emsdk_master_server + 'emsdk_add_path.bat', emsdk_path(), download_even_if_exists=True)
-    download_text_file(emsdk_master_server + 'emcmdprompt.bat', emsdk_path(), download_even_if_exists=True)
-    download_text_file(emsdk_master_server + 'emsdk.bat', emsdk_path(), download_even_if_exists=True)
+    download_text_file(urlparse.urljoin(emsdk_master_server, 'emsdk_add_path.bat'), emsdk_path(), download_even_if_exists=True)
+    download_text_file(urlparse.urljoin(emsdk_master_server, 'emcmdprompt.bat'), emsdk_path(), download_even_if_exists=True)
+    download_text_file(urlparse.urljoin(emsdk_master_server, 'emsdk.bat'), emsdk_path(), download_even_if_exists=True)
   else:
-    download_text_file(emsdk_master_server + 'emsdk_add_path', emsdk_path(), download_even_if_exists=True)
+    download_text_file(urlparse.urljoin(emsdk_master_server, 'emsdk_add_path'), emsdk_path(), download_even_if_exists=True)
   print 'Update complete.'
   
 def load_sdk_manifest():
@@ -597,7 +597,7 @@ def load_sdk_manifest():
 
 def install(): # TODO: Add parameter to choose which SDK to install.
   download_and_unzip('clang_3.2_32bit.zip', 'clang/3.2_32bit/')
-  download_file(emsdk_master_server + 'node_0.10.17_32bit.exe', 'node/0.10.17_32bit/node.exe')  
+  download_file(urlparse.urljoin(emsdk_master_server, 'node_0.10.17_32bit.exe'), 'node/0.10.17_32bit/node.exe')  
   download_and_unzip('python_2.7.5.1_32bit.zip', 'python/2.7.5.1_32bit/')
   download_and_unzip('git_1.8.3.zip', 'git/1.8.3/')
   #git_clone_checkout_and_pull(emscripten_git_repo, 'emscripten/', 'incoming')