function Trim(s) {
    return s.split(" ").join("");
}

function validateLogin(baseControlId, UserNameOnly) {
    if (typeof(UserNameOnly) == "undefined") {UserNameOnly = false;}
    var errMsg = new Array();
    checkLoginField(errMsg, baseControlId, "txtUserName", "user name");
    if (!UserNameOnly) {
        checkLoginField(errMsg, baseControlId, "txtPassword", "password");
    }
    document.getElementById(baseControlId + "_lblErrorMsg").innerHTML = errMsg.join("<BR>");
    return (errMsg.length == 0);
}

function checkLoginField(errMsgArray, baseControlId, loginFieldId, errorCaption) {
    var fld = document.getElementById(baseControlId + "_" + loginFieldId);
    var fldEmpty = (Trim(fld.value) == "");
    fld.className = (fldEmpty) ? "loginFldErr" : "loginFld";
    if (fldEmpty) {errMsgArray.push("Enter a " + errorCaption);}
    if (errMsgArray.length == 1) 
    {
        if (fldEmpty)
        {
            fld.focus();
        }
    }
}