求教一个JS判断问题

Question

<object type="application/x-shockwave-flash" data="vcastr3.swf" width="554" height="310" id="vcastr3">
        <param name="movie" value="vcastr3.swf" />
        <param name="allowFullScreen" value="true" />
        <param name="FlashVars" value="xml=
                <vcastr>
        <config>
        <bufferTime>4</bufferTime>
        <contralPanelAlpha>0.7</contralPanelAlpha>
        <controlPanelBgColor>0x000000</controlPanelBgColor>
        <controlPanelBtnColor>0xffffff</controlPanelBtnColor>
        <contralPanelBtnGlowColro>0xffff00</contralPanelBtnGlowColro>
        <controlPanelMode>normal</controlPanelMode>
        <defautVolume>0.58</defautVolume>
        <isAutoPlay>ture</isAutoPlay>
        <isLoadBegin>false</isLoadBegin>
        <isShowAbout>false</isShowAbout>
        <scaleMode>showAll</scaleMode>
        <isRepeat>false</isRepeat>
    </config>
        <plugIns>
            <beginEndImagePlugIn>
            <url>beginEndImagePlugIn.swf</url>
            <source>[!--bnimage--]</source>
            <type>begin</type>
            <scaleType>exactFit</scaleType>
        </beginEndImagePlugIn>
        </plugIns>
             <channel>
            <item>
                <source>[!--flvurl--]</source>
            </item>
        </channel>
    
    </vcastr>"/>
      </object>  
[!--flvurl--]为帝国的一个标签，当这个标签为空的时候，把这一段代码隐藏。求解！！！！

Answer 1

<script type="text/javascript">
<!--
var aa= document.getElementById("vcastr3").getElementsByTagName("param");
alert(aa.length)
for (var i=0;i<aa.length ;i++ )
{
if (aa[i].name=="FlashVars")
{
kk = aa[i].value;
if (kk.indexOf("<source>[!--flvurl--]</source>")>=0)
{
document.getElementById("vcastr3").style.display="none";
}
break;
}
}
//-->
</script>

Answer 2

这样写，有FLV地址也被隐藏了！

Answer 3

这样？
<script type="text/javascript">
<!--
var aa = document.getElementById("vcastr3").getElementsByTagName("param");
for (var i = 0; i < aa.length; i++) {
if (aa[i].name == "FlashVars") {
kk = aa[i].value;
var doc = new xml(kk.substr(4));
var item = doc.selectSingleNode("/vcastr/channel/item/source").text;
alert(item);
if(item=="")document.getElementById("vcastr3").style.display="none";
break;
}
} //创建一个dom对象
function xml(str) {
if (window.DOMParser) //firefox内核的浏览器
{
var p = new DOMParser();
return p.parseFromString(str, "text/xml");
} else if (window.ActiveXObject) //ie内核的浏览器
{
var doc = new ActiveXObject("Msxml2.DOMDocument");
doc.loadXML(str);
return doc;
} else return false;
}
//-->
</script>

Answer 4

把这句if (kk.indexOf("<source>[!--flvurl--]</source>")>=0)
改成这个if (kk.indexOf("[!--flvurl--]")<=0)
就好了  谢谢了