生成唯一ID客戶端（使用Javascript）的最佳方法

Question

我需要在瀏覽器中生成唯一的ID。目前，我使用的是這樣的：

Math.floor(Math.random() * 10000000000000001) 

我想使用當前的UNIX時間（(new Date).getTime()），但我很擔心，如果兩個客戶端在確切同時生成的ID，他們止跌不是唯一的。

我可以使用當前的UNIX時間嗎（我想因爲那種方式ID會存儲更多的信息）？如果沒有，什麼是做到這一點的最好辦法

Answer 1

您可以使用以下鏈接創建一個GUID（也許UNIX時間+ 2張的隨機數？）：

http://softwareas.com/guid0-a-javascript-guid-generator

Create GUID/UUID in JavaScript?

這將最大化你的「獨特性」的機會。

或者，如果它是安全頁面，則可以將日期/時間與用戶名連接起來以防止同時生成多個值。

Answer 2

https://github.com/broofa/node-uuid提供基於時間戳或隨機＃的符合RFC的UUID。沒有依賴關係的單一文件，支持時間戳或隨機的基於UUID，使用本機API加密質量的隨機數（如果可用）以及其他好東西。

Answer 3

var c = 1; 
function cuniq() { 
    var d = new Date(), 
     m = d.getMilliseconds() + "", 
     u = ++d + m + (++c === 10000 ? (c = 1) : c); 

    return u; 
} 

Answer 4

這是我的javascript代碼來生成guid。它快速六角映射和非常高效：

AuthenticationContext.prototype._guid = function() { 
    // RFC4122: The version 4 UUID is meant for generating UUIDs from truly-random or 
    // pseudo-random numbers. 
    // The algorithm is as follows: 
    //  Set the two most significant bits (bits 6 and 7) of the 
    //  clock_seq_hi_and_reserved to zero and one, respectively. 
    //  Set the four most significant bits (bits 12 through 15) of the 
    //  time_hi_and_version field to the 4-bit version number from 
    //  Section 4.1.3. Version4 
    //  Set all the other bits to randomly (or pseudo-randomly) chosen 
    //  values. 
    // UUID     = time-low "-" time-mid "-"time-high-and-version "-"clock-seq-reserved and low(2hexOctet)"-" node 
    // time-low    = 4hexOctet 
    // time-mid    = 2hexOctet 
    // time-high-and-version = 2hexOctet 
    // clock-seq-and-reserved = hexOctet: 
    // clock-seq-low   = hexOctet 
    // node     = 6hexOctet 
    // Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx 
    // y could be 1000, 1001, 1010, 1011 since most significant two bits needs to be 10 
    // y values are 8, 9, A, B 
    var guidHolder = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'; 
    var hex = 'abcdef'; 
    var r = 0; 
    var guidResponse = ""; 
    for (var i = 0; i < 36; i++) { 
     if (guidHolder[i] !== '-' && guidHolder[i] !== '4') { 
      // each x and y needs to be random 
      r = Math.random() * 16 | 0; 
     } 

     if (guidHolder[i] === 'x') { 
      guidResponse += hex[r]; 
     } else if (guidHolder[i] === 'y') { 
      // clock-seq-and-reserved first hex is filtered and remaining hex values are random 
      r &= 0x3; // bit and with 0011 to set pos 2 to zero ?0?? 
      r |= 0x8; // set pos 3 to 1 as 1??? 
      guidResponse += hex[r]; 
     } else { 
      guidResponse += guidHolder[i]; 
     } 
    } 

    return guidResponse; 
}; 

Answer 5

在現代瀏覽器，您可以使用crypto：

var array = new Uint32Array(1); 
window.crypto.getRandomValues(array); 
console.log(array);