function addLoadEvent(func){

var oldonload=window.onload;

if(typeof window.onload!='function')

    window.onload = func;

else

    window.onload=function(){

      if(oldonload)

        oldonload();

      func();

      }

}



addLoadEvent(function(){

    var inpMessage="cerca...";

    var el=document.getElementById("keywords");

    el.value=inpMessage;

    el.onclick=function(){if(el.value==inpMessage) el.value=""}

    el.onblur=function(){if(el.value=="") el.value=inpMessage}

    });