function ltrim(s) {  return s.replace(/^\s+/, "");}
	
function rtrim(s) {  return s.replace(/\s+$/, "");}+

function trim(s) {  return rtrim(ltrim(s));}	
	
function validar_busq(form){
	if (form.buscar.value=="" || trim(form.buscar.value)==""){
		alert("Debe ingresar un criterio de busqueda.");
		return false;
	}
	form.buscar.value = trim(form.buscar.value);
	return true;
}