根据条件生成的input 为什么在JS中取其value的时候是undefined

Question

<table width=96% border=1 align='center'  bordercolor='#999999'  cellspacing='0' style="WORD-BREAK: break-all">
      <%
          //拆分过滤字段生成input，用,号分割          String[] filter_str=filter.split(",");
          int i=0;          for(;i<filter_str.length ;i++)
          {
              String checkValue=filter_str[i];                out.print ("<script language='javascript'>"+
                        "param[" +i+ "]='" +filter_str[i]+ "';"+
"</script>");
              String desc=com.Util .DBCtl .getParamDesc(filter_str[i]);
              if(checkValue.equals("FILESIZE"))//智能分类 文件大小
              {
                  %>
                  <tr='td_' height=35>
                  <td class="td_" ><%=desc%>：</td><td class="inputa" >
                  <select name=com id=com>
                  <option value=1>>=</option>
                  <option value=2><=</option>
                  <option value=3>=</option>
                  </select>
                  <input type=input name=<%=checkValue%> id=<%=checkValue%> >
                  </td>
                  </tr>
                  <%
              }
                            else{
                  %>
                  <tr='td_' height=35>
                  <td class="td_" ><%=desc%>：</td><td class="inputa" >
                  <input type=input name=<%=checkValue%> id=<%=checkValue%> >
                  </td>
                  </tr>
      <%
              }
          }       %>
       <tr>
<td align="center" colspan=2><input type=button name=b id=b value="过滤" onclick="comm(1);"><input type=button name=c id=c value="保留" onclick="comm(2);"></td>
</tr>
</table>
  </form>
  </body>
</html>
<script>
    function comm(flag){
         frm.flag.value=flag;
         alert(frm.flag.value);
         for(var i=0;i<<%=i%>;i++)
         {
            var str="frm."+param[0];
            alert(str.value);
            if((str.value)==undefined)
            {            }
            else
            {
                  if(param[i]=='FILESIZE'||param[i]=='LENGTH'||param[i]=='COUNT')
                {
                    if(isNaN(praseInt(str.value)))
                    {
                        alert("请输入一个数字!");
                        return ;
                    }
                }                if(param[i]=='SRCIP'||param[i]=='DESTIP'||param[i]=='SRCADDR'||param[i]=='DESTADDR')
                {
                     if(!ipvalidate(str.value))
                     {
                         alert("请输入一个正确IP！");
                         return;
                     }
                }
            }
         }
         frm.submit();
         return true;
    }
</script>

Answer 1

上面代码是生成input和验证input的代码

Answer 2

如果param[0]的值可以匹配input中的某个name
试试下面的写法:
var str="frm."+param[0];
alert(eval(str.value));

Answer 3

不行啊 下面是我页面的源码
<table width=96% border=1 align='center'  bordercolor='#999999'  cellspacing='0' style="WORD-BREAK: break-all">
      <script language='javascript'>param[0]='SRCADDR';</script>
                  <tr='td_' height=35>
                  <td class="td_" >发送IP：</td><td class="inputa" >
                  <input type=input name=SRCADDR id=SRCADDR >
                  </td>
                  </tr>
      <script language='javascript'>param[1]='DESTADDR';</script>
                  <tr='td_' height=35>
                  <td class="td_" >接收IP：</td><td class="inputa" >
                  <input type=input name=DESTADDR id=DESTADDR >
                  </td>
                  </tr>
      <script language='javascript'>param[2]='SRCPORT';</script>
                  <tr='td_' height=35>
                  <td class="td_" >源端口：</td><td class="inputa" >
                  <input type=input name=SRCPORT id=SRCPORT >
                  </td>
                  </tr>
      <script language='javascript'>param[3]='DESTPORT';</script>
                  <tr='td_' height=35>
                  <td class="td_" >宿端口：</td><td class="inputa" >
                  <input type=input name=DESTPORT id=DESTPORT >
                  </td>
                  </tr>
      <script language='javascript'>param[4]='SUBJECT';</script>
                  <tr='td_' height=35>
                  <td class="td_" >主题：</td><td class="inputa" >
                  <input type=input name=SUBJECT id=SUBJECT >
                  </td>
                  </tr>
      <script language='javascript'>param[5]='ABSTRACT';</script>
                  <tr='td_' height=35>
                  <td class="td_" >摘要：</td><td class="inputa" >
                  <input type=input name=ABSTRACT id=ABSTRACT >
                  </td>
                  </tr>
      <script language='javascript'>param[6]='ISREAD';</script>
                  <tr='td_' height=35>
                  <td class="td_" >是否阅读：</td><td class="inputa" >                  <select name=ISREAD id=ISREAD>
                  <option value="-1">全部</option>
                  <option value="0">未读</option>
                  <option value="1">已读</option>
                  </select>
                  </td>
                  </tr>
                  <script language='javascript'>param[7]='FILESIZE';</script>
                  <tr='td_' height=35>
                  <td class="td_" >文件大小：</td><td class="inputa" >
                  <select name=com id=com>
                  <option value=1>>=</option>
                  <option value=2><=</option>
                  <option value=3>=</option>
                  </select>
                  <input type=input name=FILESIZE id=FILESIZE >
                  </td>
                  </tr>
                  
       <tr>
<td align="center" colspan=2><input type=button name=b id=b value="过滤" onclick="comm(1);"><input type=button name=c id=c value="保留" onclick="comm(2);"></td>
</tr>
</table>
  </form>
  </body>
</html>
<script>
    function comm(flag){
         frm.flag.value=flag;
         alert(frm.flag.value);
         for(var i=0;i<8;i++)
         {
            var str="frm."+param[0];
            alert(eval(str.value));
            if((str.value)==undefined)
            {            }
            else
            {
                  if(param[i]=='FILESIZE'||param[i]=='LENGTH'||param[i]=='COUNT')
                {
                    if(isNaN(praseInt(str.value)))
                    {
                        alert("请输入一个数字!");
                        return ;
                    }
                }                if(param[i]=='SRCIP'||param[i]=='DESTIP'||param[i]=='SRCADDR'||param[i]=='DESTADDR')
                {
                     if(!ipvalidate(str.value))
                     {
                         alert("请输入一个正确IP！");
                         return;
                     }
                }
            }
         }
         frm.submit();
         return true;
    }

Answer 4

var str="frm."+param[0]+".value";
alert(eval(str));
这样就可以了  解决了 谢谢 呵呵