户端页面中读取串口操作

<object classid="clsid:648A5600-2C6E-101B-82B6-000000000014" id="MSComm1" codebase="C:WINDOWSsystemMSCOMM32.OCX"
    type="application/x-oleobject" style="left: 54px; top: 14px">
    <param name="CommPort" value="1 " />
    <param name="DTREnable" value="1" />
    <param name="Handshaking" value="0" />
    <param name="InBufferSize" value="1024" />
    <param name="InputLen" value="0" />
    <param name="NullDiscard" value="0" />
    <param name="OutBufferSize" value="512" />
    <param name="ParityReplace" value="63" />
    <param name="RThreshold" value="0" />
    <param name="RTSEnable" value="0" />
    <param name="BaudRate" value="9600" />
    <param name="ParitySetting" value="0" />
    <param name="DataBits" value="8" />
    <param name="StopBits" value="0" />
    <param name="SThreshold" value="0 " />
    <param name="EOFEnable" value="0" />
    <param name="InputMode" value="0" />
</object>

JS代码 

//重写 mscomm 控件的唯一事件处理代码
    function MSComm1_OnComm()
    {
        var len=0;;
        if(MSComm1.CommEvent==1)//如果是发送事件
        {
          window.alert("请读条码");//这句正常，说明发送成功了
        }
        else if(MSComm1.CommEvent==2)//如果是接收事件
        {
        //  window.alert(MSComm1.CommEvent);//！ ‘
        //  window.alert(MSComm1.Input);
            document.form1.txtReceive.value=document.form1.txtReceive.value + MSComm1.Input;
        }
        // return false;
    }


//打开端口并发送命令程序
function OpenPort()
{
    if(MSComm1.PortOpen==false)
    {
        MSComm1.PortOpen=true;
        MSComm1.Output="R";//发送命令
    }
    else
    {
      window.alert ("已经开始接收数据!");
    }
}