function setFocus(obj, defaultValue) {
    if (obj.value == defaultValue) {
        obj.value = "";
    }
}

function setBlur(obj, defaultValue) {
    if (trim(obj.value) == "") {
        obj.value = defaultValue;
    }
}

function trim(str, chars) {
    return ltrim(rtrim(str, chars), chars);
}

function ltrim(str, chars) {
    chars = chars || "\\s";
    return str.replace(new RegExp("^[" + chars + "]+", "g"), "");
}

function rtrim(str, chars) {
    chars = chars || "\\s";
    return str.replace(new RegExp("[" + chars + "]+$", "g"), "");
}