【JavaScript】（5）——JavaScript与cookie、XML交互

//创建cookie
function setCookie(name,value,expires,path,domain,secure){
var cookieName=encodeURIComponent(name)+'='+encodeURIComponent(value);
if(expires instanceof Date) {
cookieName+=';expires='+expires;
}
if(path){
cookieName+=';path='+expires;
}
if(domain){
cookieName+=';domain='+domain;
}
if(secure){
cookieName+=';secure';
}
document.cookie=cookieName;
}

//失效天数，直接传一个天数即可
function setCookieDate(day) {
var date = null;
if (typeof day== 'number' && day> 0){
var date = new Date();
date.setDate(date.getDate() + day);
} else {
throw new Error('传递的day必须是一个天数，必须比0大');
}
return date;
}

//今天是2015年12月6日，7天后此cookie过期
setCookie('user','何丽杰',setCookieDate(7));
setCookie('url','baidu.com',setCookieDate(7));
setCookie('email','helijie92902@163.com',setCookieDate(7));

//获取cookie
function getCookie(name){
var cookieName=encodeURIComponent(name)+'=';   //cookieName得到user或者URL或者Email
var cookieStart=document.cookie.indexOf(cookieName); //cookieStart得到三者中的未知，user是0，URL是34，Email是48，不存在是-1
var cookieValue=null;
if(cookieStart>-1){
var cookieEnd = document.cookie.indexOf(';', cookieStart); //cookieEnd得到user的结尾是32，URL是46，Email是-1
if (cookieEnd == -1) {
cookieEnd = document.cookie.length;   //Email是74
}
cookieValue=decodeURIComponent(document.cookie.substring(cookieStart + cookieName.length, cookieEnd)); //解码
}
return cookieValue;
}

//删除 cookie
function unsetCookie(name) {
document.cookie = name +"= ; expires=" + newDate(0);
}

alert(getCookie('user'));
alert(getCookie('url'));
alert(getCookie('email'));

//跨浏览器返回XML DOM对象
function getXMLDOM(xmlStr) {
var xmlDom = null;

if (typeof window.DOMParser != 'undefined') {   //W3C
xmlDom = (new DOMParser()).parseFromString(xmlStr, 'text/xml');
var errors = xmlDom.getElementsByTagName('parsererror');
if (errors.length > 0) {
throw new Error('XML解析错误： ' + errors[0].firstChild.nodeValue);
}
} else if (typeof window.ActiveXObject != 'undefined') { //IE
var version = [
'MSXML2.DOMDocument.6.0',
'MSXML2.DOMDocument.3.0',
'MSXML2.DOMDocument'
];

for (var i = 0; i < version.length; i ++) {
try {
xmlDom = newActiveXObject(version[i]);
} catch (e) {
//跳过
}
}

//加载XML字符串
xmlDom.loadXML(xmlStr);
if (xmlDom.parseError != 0) {
throw new Error('XML解析错误： ' + xmlDom.parseError.reason);
}
} else {
throw new Error('您所使用的系统或浏览器不支持 XMLDOM！ ');
}
return xmlDom;
}

//其次，必须跨浏览器序列化XML
function serializerXML(xmlDom){
var xml='';
if(typeof XMLSerializer!='undefined'){
xml=(new XMLSerializer()).serializeToString(xmlDom);
}else if(typeof xmlDom.xml!='undefined'){
xml=xmlDom.xml;
}else{
throw newError('无法解析XML！ ');
}
return xml;
}

var xmlStr = '<root><user>helijie</user></root>';
var xmlDom = getXMLDOM(xmlStr);
alert(serializerXML(xmlDom));