Mixing JSF EL in a JavaScript file

Question

Is there a way to have Expression Language (EL) expressions included JavaScript files be evaluated by JSF?

I was hoping that Seam might have a way around this, but no luck so far. All I want is to be able to use localized messages in my JavaScript functions which are shared across pages.

Answer 1

Five ways:

1. Declare it as global variable in the parent JSF page.

   <script type="text/javascript" src="script.js"></script>
   <script type="text/javascript">
       var messages = [];
       <ui:repeat value="#{bean.messages}" var="message">
           messages['#{message.key}'] = '#{message.value}';
       </ui:repeat>
   </script>
   

   Or, if it's in JSON format already.

   <script type="text/javascript" src="script.js"></script>
   <script type="text/javascript">var messages = #{bean.messagesAsJson};</script>
   

2. Put the whole <script> in a XHTML file and use ui:include to include it.

   <script type="text/javascript" src="script.js"></script>
   <ui:include src="script-variables.xhtml" />
   

3. Pass *.js through the JspServlet (only if it's enough to evaluate only the ${} expressions). E.g. in web.xml (the <servlet-name> of JspServlet can be found in web.xml of the servletcontainer in question, it's usually jsp).

   <servlet-mapping>
       <servlet-name>jsp</servlet-name>
       <url-pattern>*.js</url-pattern>
   </servlet-mapping>
   

4. Make use of "good old" JSP with a modified content type. Rename script.js to script.jsp and add the following line to top of JSP (only if it's enough to evaluate only the ${} expressions):

   <%@page contentType="text/javascript" %>
   

5. Let JS obtain the data ajaxically during load. Here's a jQuery targeted example.

   $.getJSON('json/messages', function(messages) {
       $.each(messages, function(key, value) {
           $.messages[key] = value;
       });
   });
   

Answer 2

Since I don't like techniques that won't let the browser cache the localized Strings, I used the following technique to localize JavaScript alerts, etc. It seems a good fit if the Strings that you need in your JavaScript code are different from the ones needed by the Web server:

<h:head>
    <h:outputScript library="javascript" name="#{fw.JsFwStrings}" />
    ...

I then assign the resource string JsFwStrings to the filename of the JavaScript file defining the localized strings for the given language.

For example, the fw_en.properties file contains the entry JsFwStrings=JsFwStrings_en.js

And the JsFwStrings_en.js file contains

var TosFramework = TosFramework || {};
TosFramework.Strings = {
    UnSavedChangesWarning : 'You have unsaved changes.',
    CancelConfirmQuestion : 'Are you sure you want to cancel?'
}