跪求用js写限制table里的checkbox每行的复选框的选择，并且每行限制的个数不同
如图所示： 这个用table写的 checkbox放在<td>标签里，我之前写的那个是table里全部的复选框，多选了会提示只能选几个。代码是这样的：

<script type="text/javascript">
    function setCheckValue() {
        var obj = document.getElementById("MainContent_hdTimesCheckValue");
        var cheked_num=0; //准备选择的checkbox
        var hadcheked_num=0; //已经选择的checkbox
        var count_num = <%=lg.ToInt(practiceCountTimes)%>;
        if (obj != undefined && obj != null) {
            var chk = document.getElementsByName("chkPracticeTimes");
            if (chk != undefined && chk != null) {
                obj.value = "";
                if (chk.length == undefined) {
                    if (chk.checked) obj.value = chk.valueOf;
                } else {
  
                    for (var i = 0; i < chk.length; i++) {
                        if (chk[i].checked) {
                            cheked_num+=1;
                            if (count_num!=0&&cheked_num>count_num) {
                                alert("最多只能选"+count_num+"个！");
                                event.srcElement.checked = false;
                              //  cheked_num--;
                                i--;
                            }
                            obj.value += "|" + chk[i].value;    &n