function BitVector(data) {
    this.data = data == null ? [0] : data;
}

BitVector.prototype.and = function (other) {
    var data = new Array();
    var newLen = Math.max(other.data.length, this.data.length);

    for (var i = 0; i < newLen; i++) {
        data[i] = this.data[i] & other.data[i];
    }

    return new BitVector(data);
}

BitVector.prototype.or = function (other) {
    var data = new Array();
    var newLen = Math.max(other.data.length, this.data.length);

    for (var i = 0; i < newLen; i++) {
        data[i] = this.data[i] | other.data[i];
    }

    return new BitVector(data);
}

BitVector.prototype.xor = function (other) {
    var data = new Array();
    var newLen = Math.max(other.data.length, this.data.length);

    for (var i = 0; i < newLen; i++) {
        data[i] = this.data[i] ^ other.data[i];
    }

    return new BitVector(data);
}

BitVector.prototype.not = function () {
    var data = new Array();

    for (var i = 0; i < this.data.length; i++) {
        data[i] = ~this.data[i]
    }

    return new BitVector(data);
}

BitVector.prototype.empty = function () {
    for (var i = 0; i < this.data.length; i++) {
        if (this.data[i] != 0) return false;
    }
    return true;
}

BitVector.prototype.count = function () {
    var c = 0;
    for (var i = 0; i < this.data.length; i++) {
        var v = this.data[i];
        if (v > 0) {
            for (b = 0; b < 32; b++) {
                var bitMask = Math.pow(2, b);
                c += (bitMask & v) != 0;
            }
        }
    }

    return c;
}

BitVector.prototype.clone = function () {
    var data = new Array();
    for (var i = 0; i < this.data.length; i++) {
        data[i] = this.data[i];
    }
    return new BitVector(data);
}

BitVector.prototype.testBit = function (index) {
    var bitPos = index % 32;
    var val = this.data[(index - bitPos) / 32];
    var bitMask = Math.pow(2, bitPos);
    return (bitMask & val) != 0;
}

BitVector.prototype.setBit = function (index, value) {
    var bitPos = index % 32;
    var bitMask = Math.pow(2, bitPos);
    var arrPos = (index - bitPos) / 32;

    if (arrPos >= this.data.length) {
        for (var i = this.data.length; i < arrPos + 1; i++) this.data[i] = 0;
    }

    if (value) {
        // Oder-Verknüpfung der Bitmask
        this.data[arrPos] |= bitMask;
    }
    else {
        // Und-Verknüpfung des Komplements der Bitmask
        this.data[arrPos] &= ~bitMask;
    }
}

BitVector.prototype.toString = function () {
    var s = "";

    for (var i = 0; i < this.data.length * 32; i++) {
        s += this.testBit(i) ? '1' : '0';
    }

    return s;
}

Shows how to implement a primitive bit vector in js

BitVector in JS

JavaScript