介绍一个判断plug-ins/ActiveX 是否存在的例子

这里就以在ie3.02和netscape3+的浏览器为例，介绍关于flash(以flash2为例)插件是否安装.
<%  
    a = lcase(request.servervariables("http_user_agent"))
    if instr(a,"msie")>0 then
        if instr(a,"98")>0 or instr(a,"95")>0 or instr(a,"nt")>0 then
            ie32="true"
             ie 3 or greater on 32-bit
        end if
    elseif instr(a,"mozilla/3")>0 or instr(a,"mozilla/4")>0 then
        if instr(a,"opera")<=0 then
            nn="true"
             netscape 3 or greater
        end if
    end if

    if ie32 then
%>

    <script language="vbscript">
    if scriptenginemajorversion > 1 then
        on error resume next
        fin=(isobject(createobject("shockwaveflash.shockwaveflash")))
        if fin then
            msgbox "flash插件已安装!"
        else
            msgbox "flash插件没安装."
        end if
    end if
    </script>

<%
    elseif nn then
%>

    <script language="javascript">
    fin = navigator.plugins["shockwave flash 2.0"];
    if (fin)
    {
        alert("flash插件已安装!");
    }
    else
    {
        alert("flash插件没安装.");
    }
    </script>

<%
    end if
%>