var max=250;
var ancho=300;
function progreso_tecla(obj) {
  var progreso = document.getElementById("progreso");  
  if (obj.value.length < max) {
    progreso.style.backgroundColor = "#FFFFFF";    
    progreso.style.backgroundImage = "url(admin/img/textarea.png)";    
    progreso.style.color = "#000000";
    var pos = ancho-parseInt((ancho*parseInt(obj.value.length))/250);
    progreso.style.backgroundPosition = "-"+pos+"px 0px";
  } else {
    progreso.style.backgroundColor = "#CC0000";    
    progreso.style.backgroundImage = "url()";    
    progreso.style.color = "#FFFFFF";
  } 
  progreso.innerHTML = "("+obj.value.length+" / "+max+")";
}