JS本地存储信息的实现方式（localStorage 与 userData）

<script type="text/javascript">
(function() {
window.localData = {
hname : location.hostname ? location.hostname : 'localStatus',
isLocalStorage : window.localStorage ? true : false,
dataDom : null,
initDom : function() {
if (!this.dataDom) {
try {
this.dataDom = document.createElement('input');
this.dataDom.type = 'hidden';
this.dataDom.style.display = "none";
this.dataDom.addBehavior('#default#userData');
document.body.appendChild(this.dataDom);
var exDate = new Date();
exDate = exDate.getDate() + 30;
this.dataDom.expires = exDate.toUTCString();
} catch (ex) {
return false;
}
}
return true;
},
set : function(key, value) {
if (this.isLocalStorage) {
window.localStorage.setItem(key, value);
} else {
if (this.initDom()) {
this.dataDom.load(this.hname);
this.dataDom.setAttribute(key, value);
this.dataDom.save(this.hname)
}
}
},
get : function(key) {
if (this.isLocalStorage) {
return window.localStorage.getItem(key);
} else {
if (this.initDom()) {
this.dataDom.load(this.hname);
return this.dataDom.getAttribute(key);
}
}
},
remove : function(key) {
if (this.isLocalStorage) {
localStorage.removeItem(key);
} else {
if (this.initDom()) {
this.dataDom.load(this.hname);
this.dataDom.removeAttribute(key);
this.dataDom.save(this.hname)
}
}
}
};

var text = document.getElementById('localDataHook');
var btn = document.getElementById('clearBtnHook');
window.onbeforeunload = function() {
localData.set('beiyuuData', text.value);
};

btn.onclick = function() {
localData.remove('beiyuuData');
text.value = ''
};

if (localData.get('beiyuuData')) {
text.value = localData.get('beiyuuData');
}
})();
</script>

window.onbeforeunload = function() {
if (!canLeavePage()) {
return ('确认离开当前页面吗？未保存的数据将会丢失！');
}
};