查找可以存储在其中的单个字符串的最大长度 localStorage
此代码段将查找可以在localStorage每个域中存储的字符串的最大长度。
//Clear localStorage
for (var item in localStorage) delete localStorage[item];
window.result = window.result || document.getElementById('result');
result.textContent = 'Test running…';
//Start test
//Defer running so DOM can be updated with "test running" message
setTimeout(function () {
//Variables
var low = 0,
high = 2e9,
half;
//Two billion may be a little low as a starting point, so increase if necessary
while (canStore(high)) high *= 2;
//Keep refining until low and high are equal
while (low !== high) {
half = Math.floor((high - low) / 2 + low);
//Check if we can't scale down any further
if (low === half || high === half) {
console.info(low, high, half);
//Set low to the maximum possible amount that can be stored
low = canStore(high) ? high : low;
high = low;
break;
}
//Check if the maximum storage is no higher than half
if (storageMaxBetween(low, half)) {
high = half;
//The only other possibility is that it's higher than half but not higher than "high"
} else {
low = half + 1;
}
}
//Show the result we found!
result.innerHTML = 'The maximum length of a string that can be stored in localStorage is <strong>' + low + '</strong> characters.';
//Functions
function canStore(strLen) {
try {
delete localStorage.foo;
localStorage.foo = Array(strLen + 1).join('A');
return true;
} catch (ex) {
return false;
}
}
function storageMaxBetween(low, high) {
return canStore(low) && !canStore(high);
}
}, 0);
<h1>LocalStorage single value max length test</h1>
<div id='result'>Please enable JavaScript</div>
请注意，JavaScript中字符串的长度受到限制；如果您想查看localStorage不限于单个字符串时可以存储的最大数据量，则可以使用此答案中的代码。
编辑：堆栈片段不支持localStorage，因此这是指向JSFiddle的链接。
结果
Chrome（45.0.2454.101）： 5242878个字符
Firefox（40.0.1）： 5242883个字符
Internet Explorer（11.0.9600.18036）：16386 122066 122070个字符
在Internet Explorer中，每次运行都会得到不同的结果。
