function isNumeric(co) {
  var RegExp = /^(-)?(\d*)(\.?)(\d*)$/;
  var res = co.toString().match(RegExp);
  return res;
}

function validEmail(m){
  var ret = true;
  if (m == ""){return false;}
  var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
  if (!filter.test(m)){ret = false;}
  return ret;
}

function trim(str){
  if (!str){return "";}
  if (str == ""){return "";}
  return str.replace(/^\s+|\s+$/g,"");
}