Question

我目前正在开发一个将使用HTML5的localStorage的网站。我已经阅读了有关不同浏览器的大小限制的所有内容。但是，我还没有看到任何关于如何找出localStorage实例的当前大小的内容。 This question似乎表明JavaScript没有内置的方式来显示给定变量的大小。 localStorage是否有我没见过的内存大小属性？有没有一种简单的方法可以做到这一点，我错过了？

我的网站旨在允许用户以“离线”模式输入信息，因此当存储空间几乎已满时能够向他们发出警告非常重要。

Answer 1

在JavaScript控制台中执行此代码段：

var _lsTotal=0,_xLen,_x;for(_x in localStorage){ if(!localStorage.hasOwnProperty(_x)){continue;} _xLen= ((localStorage[_x].length + _x.length)* 2);_lsTotal+=_xLen; console.log(_x.substr(0,50)+" = "+ (_xLen/1024).toFixed(2)+" KB")};console.log("Total = " + (_lsTotal / 1024).toFixed(2) + " KB");

或在书签的“位置”字段中添加此文字以方便使用

javascript: var x, xLen, log=[],total=0;for (x in localStorage){if(!localStorage.hasOwnProperty(x)){continue;} xLen =  ((localStorage[x].length * 2 + x.length * 2)/1024); log.push(x.substr(0,30) + " = " +  xLen.toFixed(2) + " KB"); total+= xLen}; if (total > 1024){log.unshift("Total = " + (total/1024).toFixed(2)+ " MB");}else{log.unshift("Total = " + total.toFixed(2)+ " KB");}; alert(log.join("\n"));

P.S。片段根据评论中的请求进行更新。现在计算包括密钥本身的长度。每个长度乘以2，因为javascript中的char存储为UTF-16（占用2个字节）

P.P.S。应该可以在Chrome和Firefox中使用。

Answer 2

关于@Shourav上面所说的内容，我编写了一个小函数，它应该准确地获取所有localStorage个键（对于当前域）并计算组合大小，以便准确知道内存是多少由localStorage对象占用：

var localStorageSpace = function(){
        var allStrings = '';
        for(var key in window.localStorage){
            if(window.localStorage.hasOwnProperty(key)){
                allStrings += window.localStorage[key];
            }
        }
        return allStrings ? 3 + ((allStrings.length*16)/(8*1024)) + ' KB' : 'Empty (0 KB)';
    };

我的回复："30.896484375 KB"

Answer 3

IE具有Storage对象的remainingSpace属性。其他浏览器目前没有相应的内容。

我相信默认的空间量是5MB，虽然我没有亲自测试过。

Answer 4

以下是一个简单的example如何执行此操作，并且应该适用于每个浏览器

alert(1024 * 1024 * 5 - unescape(encodeURIComponent(JSON.stringify(localStorage))).length);

Answer 5

希望这能有所帮助。

因为jsfiddle上的Jas-示例对我不起作用，我想出了这个解决方案。（感谢Serge Seletskyy和Shourav在下面的代码中使用的位数）

下面是可用于测试localStorage可用空间的函数，以及（如果任何键已经在lS中）剩余多少空间。

这是一种蛮力，但它几乎适用于所有浏览器......除了Firefox。在桌面FF中，它需要很长时间（4-5分钟）才能完成，而在Android上它只会崩溃。

该功能下面是我在不同平台上的不同浏览器中完成的测试的简短摘要。享受！

function testLocalStorage() {
    var timeStart = Date.now();
    var timeEnd, countKey, countValue, amountLeft, itemLength;
    var occupied = leftCount = 3; //Shurav's comment on initial overhead
//create localStorage entries until localStorage is totally filled and browser issues a warning.
    var i = 0;
    while (!error) {
        try {
//length of the 'value' was picked to be a compromise between speed and accuracy, 
// the longer the 'value' the quicker script and result less accurate. This one is around 2Kb 
            localStorage.setItem('testKey' + i, '11111111112222222222333333333344444444445555555555666661111111111222222222233333333334444444444555555555566666');
        } catch (e) {
            var error = e;
        }
        i++;
    }
//if the warning was issued - localStorage is full.
    if (error) {
//iterate through all keys and values to count their length
        for (var i = 0; i < localStorage.length; i++) {
            countKey = localStorage.key(i);
            countValue = localStorage.getItem(localStorage.key(i));
            itemLength = countKey.length + countValue.length;
//if the key is one of our 'test' keys count it separately
            if (countKey.indexOf("testKey") !== -1) {
                leftCount = leftCount + itemLength;
            }
//count all keys and their values
            occupied = occupied + itemLength;
        }
        ;
//all keys + values lenght recalculated to Mb
        occupied = (((occupied * 16) / (8 * 1024)) / 1024).toFixed(2);
//if there are any other keys then our 'testKeys' it will show how much localStorage is left
        amountLeft = occupied - (((leftCount * 16) / (8 * 1024)) / 1024).toFixed(2);
//iterate through all localStorage keys and remove 'testKeys'
        Object.keys(localStorage).forEach(function(key) {
            if (key.indexOf("testKey") !== -1) {
                localStorage.removeItem(key);
            }
        });

    }
//calculate execution time
    var timeEnd = Date.now();
    var time = timeEnd - timeStart;
//create message
    var message = 'Finished in: ' + time + 'ms \n total localStorage: ' + occupied + 'Mb \n localStorage left: ' + amountLeft + "Mb";
//put the message on the screen
    document.getElementById('scene').innerText = message; //this works with Chrome,Safari, Opera, IE
//document.getElementById('scene').textContent = message;  //Required for Firefox to show messages
}

正如上面所承诺的，在不同的浏览器中进行了一些测试：

GalaxyTab 10.1

Maxthon Pad 1.7~1130ms 5Mb
Firefox 20.0（Beta 20.0）崩溃了
Chrome 25.0.1364.169~22250ms / 5Mb
Native（标识为Safari 4.0 / Webkit534.30）~995ms / 5Mb

iPhone 4s iOS 6.1.3

Safari~520ms / 5Mb
As HomeApp~525ms / 5Mb
iCab~710ms / 5mb

MacBook Pro OSX 1.8.3（Core 2 Duo 2.66 8Gb内存）

Safari 6.0.3~105ms / 5Mb
Chrome 26.0.1410.43~3400ms / 5Mb
Firefox 20.0 300150ms（！）/ 10Mb（抱怨脚本运行到很久）

iPad 3 iOS 6.1.3

Safari~430ms / 5Mb
iCab~595ms / 5mb

Windows 7 -64b（Core 2 Duo 2.93 6Gb内存）

Safari 5.1.7~80ms / 5Mb
Chrome 26.0.1410.43~1220ms / 5Mb
Firefox 20.0 228500ms（！）/ 10Mb（抱怨脚本运行到很久）
IE9~17900ms /9.54Mb（如果代码中的任何console.logs在打开DevTools之前不起作用）
Opera 12.15~4212ms /3.55Mb（这是选择5Mb的时候，但如果我们想要增加lS的数量，Opera会很好地问，不幸的是如果连续几次测试会崩溃）

赢8（在Parallels 8下）

IE10~7850ms /9.54Mb

Answer 6

您可以通过以下方法计算本地存储：

function sizeofAllStorage(){  // provide the size in bytes of the data currently stored
  var size = 0;
  for (i=0; i<=localStorage.length-1; i++)  
  {  
  key = localStorage.key(i);  
  size += lengthInUtf8Bytes(localStorage.getItem(key));
  }  
  return size;
}

function lengthInUtf8Bytes(str) {
  // Matches only the 10.. bytes that are non-initial characters in a multi-byte sequence.
  var m = encodeURIComponent(str).match(/%[89ABab]/g);
  return str.length + (m ? m.length : 0);
}

console.log(sizeofAllStorage());

最后，将在浏览器中记录以字节为单位的大小。

Answer 7

我会使用@tennisgen的代码来获取所有内容并计算内容，但我会自己计算密钥：

var localStorageSpace = function(){
        var allStrings = '';
        for(var key in window.localStorage){
            allStrings += key;
            if(window.localStorage.hasOwnProperty(key)){
                allStrings += window.localStorage[key];
            }
        }
        return allStrings ? 3 + ((allStrings.length*16)/(8*1024)) + ' KB' : 'Empty (0 KB)';
    };

Answer 8

除了@ serge在这里投票最多的答案外，还需要考虑密钥的大小。下面的代码将添加localStorage

中存储的密钥的大小

var t = 0; 
for (var x in localStorage) { 
    t += (x.length + localStorage[x].length) * 2; 
} 
console.log((t / 1024) + " KB");

Answer 9

根据规范，字符串的每个字符都是16位。

但是使用chrome进行检查（设置＆gt;内容设置＆gt; Cookie和网站数据）向我们展示了启动localStorage需要3kB（开销大小）

存储的数据大小遵循这种关系（精确到1kB）
3 +（（localStorage.x.length * 16）/（8 * 1024）） kB

其中localStorage.x是您的存储字符串。

Answer 10

我解决这个问题的方法是创建函数来查找本地存储中的已用空间和剩余空间，然后创建一个函数来调用这些函数来确定最大存储空间。

function getUsedSpaceOfLocalStorageInBytes() {
    // Returns the total number of used space (in Bytes) of the Local Storage
    var b = 0;
    for (var key in window.localStorage) {
        if (window.localStorage.hasOwnProperty(key)) {
            b += key.length + localStorage.getItem(key).length;
        }
    }
    return b;
}

function getUnusedSpaceOfLocalStorageInBytes() {
    var maxByteSize = 10485760; // 10MB
    var minByteSize = 0;
    var tryByteSize = 0;
    var testQuotaKey = 'testQuota';
    var timeout = 20000;
    var startTime = new Date().getTime();
    var unusedSpace = 0;
    do {
        runtime = new Date().getTime() - startTime;
        try {
            tryByteSize = Math.floor((maxByteSize + minByteSize) / 2);
            localStorage.setItem(testQuotaKey, new Array(tryByteSize).join('1'));
            minByteSize = tryByteSize;
        } catch (e) {
            maxByteSize = tryByteSize - 1;
        }
    } while ((maxByteSize - minByteSize > 1) && runtime < timeout);

    localStorage.removeItem(testQuotaKey);

    if (runtime >= timeout) {
        console.log("Unused space calculation may be off due to timeout.");
    }

    // Compensate for the byte size of the key that was used, then subtract 1 byte because the last value of the tryByteSize threw the exception
    unusedSpace = tryByteSize + testQuotaKey.length - 1;
    return unusedSpace;
}

function getLocalStorageQuotaInBytes() {
    // Returns the total Bytes of Local Storage Space that the browser supports
    var unused = getUnusedSpaceOfLocalStorageInBytes();
    var used = getUsedSpaceOfLocalStorageInBytes();
    var quota = unused + used;
    return quota;
}

Answer 11

您可以使用Blob function.获取当前本地存储数据的大小，这在旧的浏览器中可能无法使用。

示例：

public function build()
{
    $mail = $this->view('mail.test')
        ->with([
            'course' => $this->course,
            'registration' => $this->registration,
        ])
        ->subject('title' . $this->course->curriculum->code);

    foreach ($this->course->curriculum->materials()->where('type', 'Student Manual')->get() as $material) {
        $mail->attach($material->url, [
            'as' => $material->name,
        ]);
    }
    return $mail;
}

Object.values（）将localStorage对象转换为数组。 Blob将数组变成原始数据。

Answer 12

//内存占用密钥和值，因此更新了代码。

var jsonarr=[];
var jobj=null;
for(x in sessionStorage) // Iterate through each session key
{
    jobj={}; 
    jobj[x]=sessionStorage.getItem(x); //because key will also occupy some memory
    jsonarr.push(jobj);
    jobj=null;
}
//https://developer.mozilla.org/en/docs/Web/JavaScript/Data_structures 
//JavaScript's String type is used to represent textual data. It is a set of "elements" of 16-bit unsigned integer values. 
var size=JSON.stringify(jsonarr).length*2; //16-bit that's why multiply by 2
var arr=["bytes","KB","MB","GB","TB"]; // Define Units
var sizeUnit=0;
while(size>1024){ // To get result in Proper Unit
    sizeUnit++;
    size/=1024;
}
alert(size.toFixed(2)+" "+arr[sizeUnit]);

Answer 13

是的，这个问题是10年前问的。但是对于那些感兴趣的人（像我一样，我正在构建一个脱机文本编辑器以将数据存储在本地存储中）并精于编程，那么您可以使用以下简单的方法：

var warning = 1;
var limit = 2000000; //2 million characters, not really taking in account to bytes but for tested ammounts of characters stored
setInterval(function() {
    localStorage["text"] = document.getElementById("editor").innerHTML; //gets text and saves it in local storage under "text"
    if(localStorage["text"].length > limit && warning == 1){
            alert("Local Storage capacity has been filled"); 
            warning = 2; //prevent a stream of alerts
    }
}, 1000);
//setInterval function saves and checks local storage

获取已用存储量的最佳方法是查看站点设置（例如，如果您将图像存储在本地存储中）。至少在chrome中，您可以看到使用的字节数（即：1222字节）。但是，上面已经提到了用js查看填充的本地存储的最佳方法，因此请使用它们。

Answer 14

window.localStorage.remainingSpace

如何找到localStorage的大小

14 个答案: