js的ie7，8兼容问题？

Question

有点郁闷在ie8下面js代码能正确执行，但下ie7下面却出现了小的偏差
代码：
function doAdd()
        {
            var b =document.getElementById("tab_2");
            var nowTable = document.getElementById("myTable");
            b==b++;
            var newTr=nowTable.insertRow(b+1);
        var newTd1=newTr.insertCell(0);
        var newTd2=newTr.insertCell(1);
            var newTd3=newTr.insertCell(2);
            var newTd4=newTr.insertCell(3);         newTd1.innerHTML =document.getElementById("myTd1").innerHTML;
        newTd2.innerHTML =document.getElementById("myTd2").innerHTML;
        newTd3.innerHTML =document.getElementById("myTd3").innerHTML;
        newTd4.innerHTML =document.getElementById("myTd4").innerHTML;
        
        //时间
        newTd1.getElementsByTagName("input")[0].setAttribute("value","");
        newTd1.getElementsByTagName("input")[0].setAttribute("id","time"+b);
        //学习或工作单位
        newTd2.getElementsByTagName("input")[0].setAttribute("value","");
        newTd2.getElementsByTagName("input")[0].setAttribute("id","workPlace"+b);
        //专业或职位
        newTd3.getElementsByTagName("input")[0].setAttribute("value","");
        newTd3.getElementsByTagName("input")[0].setAttribute("id","workPosition"+b);
        //基本工资
        newTd4.getElementsByTagName("input")[0].setAttribute("value","");
        newTd4.getElementsByTagName("input")[0].setAttribute("id","salary"+b);
        
        document.form1.tab_2.value=b;
        //form1.listnum.value=parseInt(b)-1;
        }这段代码能动态插入表格行的代码

Answer 1

我的html代码是
<table align="center" border="1" cellspacing="0" bordercolor="#3399FF" class="css" width="100%" id="myTable">
                        <tr>
                            <td align="center" class="style8" style="font-size: 18px">
                                时间
                            </td>
                            <td style="height: 29px">
                                <center style="font-size: 18px">
                                    学习或工作单位</center>
                            </td>
                            <td style="height: 29px">
                                <center style="font-size: 18px">
                                    专业或职位</center>
                            </td>
                            <td style="height: 29px">
                                <center style="font-size: 18px">
                                    基本工资</center>
                            </td>
                        </tr>
                            
                         <tr>
                            <td align="left" class="style8" id="myTd1">
                                <span lang="EN-US" style="font-size: 13.0pt; font-family: 仿宋_GB2312;">
                                        <input type="text" name="txtWorkingTime1" class="input1_net" />
                                        <input type="hidden" name="tab_2" value="1" />
                                 </span>
                            </td>
                            <td style="height: 29px"id="myTd2">
                                <span lang="EN-US" style="font-size: 13.0pt; font-family: 仿宋_GB2312;">
                                        <input type="text" id="txtWorkplace1" name="txtWorkplace1" class="input1_net" size="35" />
                                 </span>
                            </td>
                            <td style="height: 29px" id="myTd3">
                                <span lang="EN-US" style="font-size: 13.0pt; font-family: 仿宋_GB2312;">
                                    <input type="text" id="txtWorkPosition1" name="txtWorkPosition1" class="input1_net" size="25" />
                                </span>
                            </td>
                            <td style="height: 29px" id="myTd4">
                                <span lang="EN-US" style="font-size: 13.0pt; font-family: 仿宋_GB2312;">
                                    <input type="text" id="txtBasicWage1" name="txtBasicWage1" runat="server" class="input1_net" />
                                </span> 
                                <input type="button" name="delBtn" value="删除行" onclick="doDel(this)" class="sky_blue" />                          
                            </td>
                        </tr>
                               </table>

Answer 2

正常情况下我在动态插入一行后会显示在第二个tr下，但是现在js插入后显示在第一个js上面
也就是显示在标题上面，ie8下显示正常，ie7下有问题

Answer 3

b==b++;
maybe shout be         b++

Answer 4

var b =document.getElementById("tab_2");
            var nowTable = document.getElementById("myTable");
            b==b++;
这几行代码没有问题吗？
对像可以累加吗？

Answer 5

var b =document.getElementById("tab_2").value;
(b-0)++;

Answer 6

问题在ie6，7下面解决了，把var b =document.getElementById("tab_2"); 加一个.value
在ie6，7下就正常了，8下有问题，幸好公司里那帮人都是用的6，7先这样着算了

Answer 7

var b =document.getElementById("tab_2"); 
和var b =document.getElementById("tab_2").value; 
是两个不同的对象。
前者，是一个标签元素，他代表了<input type="hidden" name="tab_2" value="1" />这个框。
后者，是这个input的一个属性，value。
楼主对这个概念没搞清楚！

Answer 8

我知道啊，即便如此，没加value的标签，在ie8下却显示正常，6，7下却有问题，这真是很郁闷