获取下拉值 及 弹出页面返回值

var obj = new Object();

    var category=document.getElementById('category');    

//获取显示内容

    obj.categoryName = category.options[category.selectedIndex].text;

//获取值

    obj.categoryId = category.options[category.selectedIndex].value;
    var grade = document.getElementById("grade");
    obj.gradeName = grade.options[grade.selectedIndex].text;
    obj.gradeId = grade.options[grade.selectedIndex].value;

window.opener == null;

//返回参数

window.returnValue = obj;
window.close();