Event.observe(window, 'load', function() {
    //google search
    $("googleSearch").value="Rechercher...";
    $("googleSearch").addEventListener('blur',function(e){
        if(Event.element(e).value=="")Event.element(e).value="Rechercher...";
    }, true);
    $("googleSearch").addEventListener('focus',function(e){
        if(Event.element(e).value=="Rechercher...")Event.element(e).value="";
    }, true);
});