function checkValue() {
    var keywordObj = document.getElementById("keyword");
    var CityId = document.getElementById("searchCityId");
    var keyword = keywordObj.value;
    if (keyword == "") {
        alert("请输入要搜索的关键词");
        keywordObj.focus();
    }
    else {
        window.open("/CmtSearch.aspx?CityId=" + CityId.value + "&CmtName=" + escape(keyword));
    }
}