function cargasonido(url){
   var className = 'sonido';
   var as = document.getElementsByTagName('a');
   for(i=0;i<as.length;i++){
      var a = as[i];
      r=new RegExp("(^| )"+className+"($| )");
      if(r.test(a.className)){
         a.onclick = function(){
			window.open(url,'AyudaSonido','height=140,width=400,menubar=0')
			window.focus()
         }
      }
    }
}