--- chrome/chromeFiles/content/browser.js	2005-12-01 04:03:36.000000000 +0000
+++ chrome/chromeFiles/content/browser.js	2006-02-10 13:22:30.000000000 +0000
@@ -66,8 +66,11 @@
   // listen for clicks on the install bar
   Components.classes["@mozilla.org/observer-service;1"]
             .getService(Components.interfaces.nsIObserverService)
             .addObserver(this, "install-userscript", true);
+  Components.classes["@mozilla.org/observer-service;1"]
+            .getService(Components.interfaces.nsIObserverService)
+            .addObserver(this, "view-source", true);
 
   // we use this to determine if we are the active window sometimes
   this.winWat = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
                           .getService(Components.interfaces.nsIWindowWatcher);
@@ -153,27 +156,41 @@
   
     GM_listen(unsafeWin, "pagehide", GM_hitch(this, "contentUnload"));
   }
 
-  if (GM_getEnabled() && href.match(/\.user\.js($|\?)/i)) {
+  if (GM_getEnabled() && href.match(/\.user\.js($|\?)/i) && !href.match(/^view-source:/i)) {
     // find the browser the user script is loading in
     for (var i = 0, browser; browser = this.tabBrowser.browsers[i]; i++) {
       if (browser.contentWindow == unsafeWin) {
         var pick = Math.round(Math.random() * (GM_BrowserUI.greetz.length - 1));
         var greeting = GM_BrowserUI.greetz[pick];
 
-        this.tabBrowser.showMessage(
-          browser,
-          "chrome://greasemonkey/content/status_on.gif",
-          greeting + " This is a Greasemonkey User Script. " + 
-                     "Click Install to start using it.",
-          "Install",
-          null /* default doc shell */,
-          "install-userscript",
-          null /* no popuup */,
-          "top",
-          true /* show close button */,
-          "I" /* access key */);
+        if (unsafeWin.document.contentType.match(/^(text\/plain|application\/(x-)?javascript)$/i)) {
+          this.tabBrowser.showMessage(
+            browser,
+            "chrome://greasemonkey/content/status_on.gif",
+            greeting + " This is a Greasemonkey User Script. " + 
+                       "Click Install to start using it.",
+            "Install",
+            null /* default doc shell */,
+            "install-userscript",
+            null /* no popuup */,
+            "top",
+            true /* show close button */,
+            "I" /* access key */);
+        } else {
+          this.tabBrowser.showMessage(
+            browser,
+            "chrome://greasemonkey/content/status_off.gif",
+            greeting + " " + "This User Script is not plain text so it cannot be installed.",
+            "View Source",
+            null /* default doc shell */,
+            "view-source",
+            null /* no popup */,
+            "top",
+            true /* show close button */,
+            null /* access key */);
+        }
 
         break;
       }
     }
@@ -189,8 +206,13 @@
     if (window == this.winWat.activeWindow) {
       new ScriptDownloader().installFromURL(
         this.tabBrowser.selectedBrowser.contentWindow.location.href);
     }
+  } else if (topic == "view-source") {
+    if (window == this.winWat.activeWindow) {
+      this.tabBrowser.selectedBrowser.contentWindow.location.replace("view-source:"
+        + this.tabBrowser.selectedBrowser.contentWindow.location.href);
+    }
   } else {
     throw new Error("Unexpected topic received: {" + topic + "}");
   }
 }