localStorage eventHandler不会被调用 [英] localStorage eventHandler Doesn't Get Called
问题描述
以下是我的代码：
< script type =text / javascript>
函数getLocalStorage（）{
尝试{
if（!! window.localStorage）return window.localStorage;
} catch（e）{
return undefined;
函数getAddEventListener（）{
尝试{
if（!! window.addEventListener）return window.addEventListener;
} catch（e）{
return undefined;
function eventHandler（e）{
alert（here we are =+ e.storageArea.traveler）;
函数testStorage（）{
var db = getLocalStorage（）;
var addEL = getAddEventListener（）;
if（addEL）{
addEL（'storage'，eventHandler，false）;
} else {
alert（'这个浏览器不支持事件监听器'）;
}
db.setItem（'traveler'，'Bill'）;
db.setItem（'destination'，'Ventura'）;
db.setItem（'transportation'，'Airplane'）;
document.getElementById（'results'）。innerHTML = db.getItem（'destination'）;
}
< / script>
< / head>
< body onload =testStorage（）;>
< div id =results> < / DIV>
< / body>
< / html>
它成功地将项目插入本地存储并显示结果'results'-element，但eventHandler doesn没有工作。我刷新浏览器窗口并没有看到任何警报消息。为什么？
因为存储事件不适用于相同的窗口/选项卡。它们仅被用于其他使用相同 localStorage 的窗口/选项卡。尝试打开两个分隔标签，并在一个插入一些数据到 localStorage 。
以下是一个类似的问题 a>，它解释了 localStorage 事件是如何工作的。
Here is my code:
<script type="text/javascript">
function getLocalStorage() {
try {
if (!! window.localStorage) return window.localStorage;
} catch(e) {
return undefined;
}
}
function getAddEventListener() {
try {
if( !! window.addEventListener ) return window.addEventListener;
} catch(e) {
return undefined;
}
}
function eventHandler(e) {
alert("here we are = " + e.storageArea.traveler);
}
function testStorage() {
var db = getLocalStorage();
var addEL = getAddEventListener();
if(addEL) {
addEL('storage', eventHandler, false);
} else {
alert('This browser does not support event listeners');
}
db.setItem('traveler', 'Bill');
db.setItem('destination', 'Ventura');
db.setItem('transportation', 'Airplane');
document.getElementById('results').innerHTML = db.getItem('destination');
}
</script>
</head>
<body onload="testStorage();">
<div id="results"> </div>
</body>
</html>
It successfully insert items in the local storage and display result in 'results'-element, but eventHandler doesn't work. I refresh the browser windows and don't see any alert messages. Why?
Because storage events don't work for same window/tab. They are fired only for other windows/tabs that use same localStorage. Try opening two separat tabs and in one insert some data to the localStorage.
Here is a similar question that explains how localStorage event works.
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