jQuery 获取和设置radio 和 checkbox 值的操作

jquery 中的val()，可以取值也可赋值，表单元素中的radio和checkbox是比较常用的控件，下面说说对它们的取值和赋值的使用

1、取值

表单如下：

<div class="items">
        @if (Model.Question.type == "单选")
        {
            <div><input type="radio" id="A" name="sin" value="A" /><label for="A"><span class="item">A</span>@Model.Question.A</label></div>
            <div><input type="radio" id="B" name="sin" value="B" /><label for="B"><span class="item">B</span>@Model.Question.B</label></div>
            <div><input type="radio" id="C" name="sin" value="C" /><label for="C"><span class="item">C</span>@Model.Question.C</label></div>
            <div><input type="radio" id="D" name="sin" value="D" /><label for="D"><span class="item">D</span>@Model.Question.D</label></div>
        }
        else if (Model.Question.type == "多选")
        {
            <div><input type="checkbox" id="A" name="mul" value="A" /><label for="A"><span class="item">A</span>@Model.Question.A</label></div>
            <div><input type="checkbox" id="B" name="mul" value="B" /><label for="B"><span class="item">B</span>@Model.Question.B</label></div>
            <div><input type="checkbox" id="C" name="mul" value="C" /><label for="C"><span class="item">C</span>@Model.Question.C</label></div>
            <div><input type="checkbox" id="D" name="mul" value="D" /><label for="D"><span class="item">D</span>@Model.Question.D</label></div>
        }
        else
        {
            <div><input type="radio" id="A" name="jul" value="@Model.Question.A" /><label for="A"><span class="item"></span>@Model.Question.A</label></div>
            <div><input type="radio" id="B" name="jul" value="@Model.Question.B" /><label for="B"><span class="item"></span>@Model.Question.B</label></div>
        }
    </div>

 jquery代码：

 $(".items input").click(function () {
        var answer = "";
        if (type == "单选") {
            answer = $(":radio[name=sin]:checked").val();
            alert(answer);
        } else if (type == "多选") {
            $(":checkbox[name=mul]:checked").each(function () {
                answer += $(this).val() + ",";
            });
        } else {
            answer = $("input:radio[name=jul]:checked").val();
        }
        $.post("/home/clickItem", { questionId: '@Model.Question.id', userAnswer: answer }, function (data) {
            if (data != "ok") {
                alert(data);
                location.href = "/home/login";
            }
        });
    });

radio 好取，只要取 :checked 选中的值，checkbox 可能是多选，需要循环取值

2、赋值

赋值可不能这样 $(":radio").val("B")，这种是不行的，使用数组的方式赋值，应该这样 $(":radio").val(["B"]) ,$(":checkbox").val(["A","C","D"]),

 if (type == "单选") {
            $(":radio[name=sin]").val([useranswer]);
        } else if (type == "多选") {
            var arr = useranswer.substring(0, useranswer.length - 1).split(","); //useranswer="B,C,D"这种形式转成数组
            $(":checkbox[name=mul]").val(arr);
        } else {
            answer = $(":radio[name=jul]").val([useranswer]);
        }