function sms_number_validation( field )
  {
    var cleanString = "";
    var dirtyString = document.getElementById(field+"_NUMBER_ID").value;

    if (dirtyString.length > 1) {
    	for (var i = 0; i < dirtyString.length; i++)
    	{
    	  if (!isNaN(dirtyString.charAt(i))) {
    	  	cleanString = cleanString + dirtyString.charAt(i);
    	  }
    	} // end for loop

    	if (cleanString.length != 10) {
    		alert('Text Message Number must be 10 digits long');
    		document.getElementById(field+"_NUMBER_ID").focus();
    		return false;
    	}
    	else {
    		document.getElementById(field).value = cleanString;
    	}

    } //end if sms number keyed

    if (document.getElementById(field+"_PROVIDER_ID").value.length > 0) {
		if (cleanString.length > 1) {
			document.getElementById(field).value = cleanString + '@' + document.getElementById(field+"_PROVIDER_ID").value;
		} else {
			alert('Text Message (SMS) Number AND Text Message (SMS) Provider are required for a valid text message setup.');
			document.getElementById(field+"_NUMBER_ID").focus();
			return false;
		}
	} else {
		if (cleanString.length > 1) {
			alert('Text Messages (SMS) Number AND Text Message (SMS) Provider are required for a valid text message setup.');
			document.getElementById(field+"_PROVIDER_ID").focus();
			return false;
		} else {
		   document.getElementById(field).value = "";
		}
	}

	return true;

  }