javascript读写XML实现广告轮换(兼容IE、FF)_javascript技巧

// JScript 文件
var Now = new Date();
var Min = Now.getSeconds();
var i;
if((Min % 2) == 1)
//读取秒数，根据奇偶随机轮换，当然也可以改变此处算法增加xml节点数
{
i = 1;
}
else
{ i = 0; }
var url = "xml/ads.xml";
String.prototype.Trim = function() {
return this.replace(/(^\s*)|(\s*$)/g, "");
}
var xmlDoc;
//判断是否为Firefox或IE
var moz = (typeof document.implementation != 'undefined') && (typeof document.implementation.createDocument != 'undefined');
var ie = (typeof window.ActiveXObject != 'undefined');
function importXML(file) {
if (moz)
{
xmlDoc = document.implementation.createDocument("", "doc", null);
//创建FIREFOX下XML文档对象
}
else if (ie)
{ xmlDoc = new ActiveXObject("MSXML2.DOMDocument.3.0");
xmlDoc.async = false;
while( xmlDoc.readyState != 4) {};
//创建IE下XML文档对象
}
xmlDoc.load(file);
}importXML(url);//载入xml
function updatetupiandizhi()
{
if (moz)
{
var ad = xmlDoc.getElementsByTagName("ad")[0];
var tupian;
var _tupian = ad.getElementsByTagName("tupian")[i].firstChild.nodeValue;
if (_tupian) tupian = _tupian.Trim();
//得到tupian,dizhi节点下的值
var dizhi;
var _dizhi=ad.getElementsByTagName("dizhi")[i].firstChild.nodeValue;
if(_dizhi) dizhi = _dizhi.Trim();
document.getElementById('tupian').href = tupian;
document.getElementById('dizhi').src = dizhi;
//实现轮换
} else if (ie)
{var src = xmlDoc.documentElement.selectNodes("tupian");
var href = xmlDoc.documentElement.selectNodes("dizhi");
//得到tupian,dizhi节点下的值
document.getElementById("dizhi").href = href(i).text;
document.getElementById("tupian").src = src(i).text;
//实现轮换
}}