diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
index d0c1b3be9ee..fb9f19ebcc5 100644
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -1736,9 +1736,14 @@ function getShortcutOrURI(aURL, aPostDataRef) {
       aPostDataRef.value = getPostDataStream(postData, param, encodedParam,
                                              "application/x-www-form-urlencoded");
   }
-  else
+  else if (param) {
+    // This keyword doesn't take a parameter, but one was provided. Just return
+    // the original URL.
     aPostDataRef.value = null;
 
+    return aURL;
+  }
+
   return shortcutURL;
 }
  
diff --git a/browser/base/content/test/Makefile.in b/browser/base/content/test/Makefile.in
index 31ed5ce22cb..cd004782602 100644
--- a/browser/base/content/test/Makefile.in
+++ b/browser/base/content/test/Makefile.in
@@ -55,6 +55,7 @@ _BROWSER_FILES = browser_bug321000.js \
                  browser_autodiscovery.js \
                  autodiscovery.html \
                  moz.png \
+                 browser_getshortcutoruri.js \
     $(NULL)
 
 libs:: $(_TEST_FILES)
diff --git a/browser/base/content/test/browser_getshortcutoruri.js b/browser/base/content/test/browser_getshortcutoruri.js
new file mode 100644
index 00000000000..a6d9a7e5510
--- /dev/null
+++ b/browser/base/content/test/browser_getshortcutoruri.js
@@ -0,0 +1,139 @@
+function makeURI(aURL, aOriginCharset, aBaseURI) {
+  var ioService = Components.classes["@mozilla.org/network/io-service;1"]
+                            .getService(Components.interfaces.nsIIOService);
+  return ioService.newURI(aURL, aOriginCharset, aBaseURI);
+}
+
+function getPostDataString(aIS) {
+  if (!aIS)
+    return null;
+
+  var sis = Cc["@mozilla.org/scriptableinputstream;1"].
+            createInstance(Ci.nsIScriptableInputStream);
+  sis.init(aIS);
+  var dataLines = sis.read(aIS.available()).split("\n");
+
+  // only want the last line
+  return dataLines[dataLines.length-1];
+}
+
+function keywordResult(aURL, aPostData) {
+  this.url = aURL;
+  this.postData = aPostData;
+}
+
+function keyWordData() {}
+keyWordData.prototype = {
+  init: function(aKeyWord, aURL, aPostData, aSearchWord) {
+    this.keyword = aKeyWord;
+    this.uri = makeURI(aURL);
+    this.postData = aPostData;
+    this.searchWord = aSearchWord;
+
+    this.method = (this.postData ? "POST" : "GET");
+  }
+}
+
+function bmKeywordData(aKeyWord, aURL, aPostData, aSearchWord) {
+  this.init(aKeyWord, aURL, aPostData, aSearchWord);
+}
+bmKeywordData.prototype = new keyWordData();
+
+function searchKeywordData(aKeyWord, aURL, aPostData, aSearchWord) {
+  this.init(aKeyWord, aURL, aPostData, aSearchWord);
+}
+searchKeywordData.prototype = new keyWordData();
+
+var testData = [
+  [new bmKeywordData("bmget", "http://bmget/search=%s", null, "foo"),
+   new keywordResult("http://bmget/search=foo", null)],
+
+  [new bmKeywordData("bmpost", "http://bmpost/", "search=%s", "foo2"),
+   new keywordResult("http://bmpost/", "search=foo2")],
+
+  [new bmKeywordData("bmpostget", "http://bmpostget/search1=%s", "search2=%s", "foo3"),
+   new keywordResult("http://bmpostget/search1=foo3", "search2=foo3")],
+
+  [new bmKeywordData("bmget-nosearch", "http://bmget-nosearch/", null, ""),
+   new keywordResult("http://bmget-nosearch/", null)],
+
+  [new searchKeywordData("searchget", "http://searchget/?search={searchTerms}", null, "foo4"),
+   new keywordResult("http://searchget/?search=foo4", null)],
+
+  [new searchKeywordData("searchpost", "http://searchpost/", "search={searchTerms}", "foo5"),
+   new keywordResult("http://searchpost/", "search=foo5")],
+
+  [new searchKeywordData("searchpostget", "http://searchpostget/?search1={searchTerms}", "search2={searchTerms}", "foo6"),
+   new keywordResult("http://searchpostget/?search1=foo6", "search2=foo6")],
+
+  // Bookmark keywords that don't take parameters should not be activated if a
+  // parameter is passed (bug 420328).
+  [new bmKeywordData("bmget-noparam", "http://bmget-noparam/", null, "foo7"),
+   new keywordResult(null, null)],
+  [new bmKeywordData("bmpost-noparam", "http://bmpost-noparam/", "not_a=param", "foo8"),
+   new keywordResult(null, null)],
+  
+  // Test escaping (%s = escaped, %S = raw)
+  // UTF-8 default
+  [new bmKeywordData("bmget-escaping", "http://bmget/?esc=%s&raw=%S", null, "foé"),
+   new keywordResult("http://bmget/?esc=fo%C3%A9&raw=foé", null)],
+  // Explicitly-defined ISO-8859-1
+  [new bmKeywordData("bmget-escaping2", "http://bmget/?esc=%s&raw=%S&mozcharset=ISO-8859-1", null, "foé"),
+   new keywordResult("http://bmget/?esc=fo%E9&raw=foé", null)],
+];
+
+function test() {
+  setupKeywords();
+
+  for each (var item in testData) {
+    var [data, result] = item;
+
+    var postData = {};
+    var query = data.keyword;
+    if (data.searchWord)
+      query += " " + data.searchWord;
+    var url = getShortcutOrURI(query, postData);
+
+    // null result.url means we should expect the same query we sent in
+    var expected = result.url || query;
+    is(url, expected, "got correct URL for " + data.keyword);
+    is(getPostDataString(postData.value), result.postData, "got correct postData for " + data.keyword);
+  }
+
+  cleanupKeywords();
+}
+
+var gBMFolder = null;
+var gAddedEngines = [];
+function setupKeywords() {
+  var searchService = Cc["@mozilla.org/browser/search-service;1"].
+                      getService(Ci.nsIBrowserSearchService);
+  gBMFolder = Application.bookmarks.addFolder("keyword-test");
+  for each (var item in testData) {
+    var data = item[0];
+    if (data instanceof bmKeywordData) {
+      var bm = gBMFolder.addBookmark(data.keyword, data.uri);
+      bm.keyword = data.keyword;
+      if (data.postData)
+        bm.annotations.set("bookmarkProperties/POSTData", data.postData, Ci.nsIAnnotationService.EXPIRE_SESSION);
+    }
+    
+    if (data instanceof searchKeywordData) {
+      searchService.addEngineWithDetails(data.keyword, "", data.keyword, "", data.method, data.uri.spec);
+      var addedEngine = searchService.getEngineByName(data.keyword);
+      if (data.postData) {
+        var [paramName, paramValue] = data.postData.split("=");
+        addedEngine.addParam(paramName, paramValue, null);
+      }
+
+      gAddedEngines.push(addedEngine);
+    }
+  }
+}
+
+function cleanupKeywords() {
+  var searchService = Cc["@mozilla.org/browser/search-service;1"].
+                      getService(Ci.nsIBrowserSearchService);
+  gBMFolder.remove();
+  gAddedEngines.map(searchService.removeEngine);
+}