This gist demonstrate how easly integrate Gettext.js + jQuery in a smart/automatized way to translate entire sites by using some ".po" file.

AutomaticSiteTranslation.js

/**
 * This is a experimental and fun script/tutorial that demonstrates how to translate sites USING Gettext
 * without use _() stuff ( or others ) in your html just by parsing all your html visible text.
 * 
 * @author Klederson Bueno <klederson@phpburn.com>
 * @see http://jsgettext.berlios.de/doc/html/Gettext.html
 * @see http://www.phpburn.com/
 * @version 0.1a
 */
var iFindTranslator = {
  t : null,
  
  /**
   * This method will perform the translation of a given container ( can be used into body element for example )
   * This will get your already implemented PO file (references bellow) and use it to translate.
   * 
   * YES I KNOW WE CAN SETUP DOMAINS AND STUFF IN HERE but remember this is just an ilustrative tutorial do all
   * the fancy stuff you want to this is just to make things work.
   * 
   * @see http://jsgettext.berlios.de/doc/html/Gettext.html
   */ 
  translate : function(container) {
    //this way will help you to save memory instead of keep creating everytime you call the translate method
    var t = this.t == null ? new Gettext() : this.t; //this assumes that you already loaded the right lang/PO file
    
    $(container).find("*").contents().filter(function () { 
     if ( this.nodeType == 3) { 
       if((this.nodeValue.toString().trim() != "")) {
         var id = this.nodeValue.toString().trim();
         this.nodeValue = this.nodeValue.replace(id,t.gettext(id)); //this will help you to preserve spaces
        }
      }
    });
  },
  
  /**
 * This method will help you to extract text from the current screen and generate the PO file
 * You'll need to copy the console output and create your .PO file
 */
  lazyExtractor : function(container) {
    $(container).find("*:visible").contents().filter(function () { //we only extract visible stuff so be sure of this
    if ( this.nodeType == 3) { 
      if((this.nodeValue.toString().trim() != "")) {
        var value = this.nodeValue.toString().trim();
        console.log('msgid "' + value + '"');
        console.log('msgstr "TRANSLATED: ' + value + '"');
      }
    }
  });
  }
}