uuid4.js

gistfile1.js

function uuid4() {
    var r = Math.random,
        p = "0000000",
        n = 0x100000000,
        a = (r() * n >>> 0).toString(16),
        b = ((r() * n & 0xffff4fff | 0x4000) >>> 0).toString(16),
        c = ((r() * n & 0xbfffffff | 0x80000000 ) >>> 0).toString(16),
        d = (r() * n >>> 0).toString(16);
    if (a.length < 8) {
        a = (p + a).slice(-8);
    }
    if (b.length < 8) {
        b = (p + b).slice(-8);
    }
    if (c.length < 8) {
        c = (p + c).slice(-8);
    }
    if (d.length < 8) {
        d = (p + d).slice(-8);
    }
    return [
        a,
        b.slice(0,4),
        b.slice(4),
        c.slice(0,4),
        c.slice(4) + d
    ].join("-");
}