test.js

console.time('matching-words');

var query = 'James Morrison Broken Strings ft. Nelly Furtado',
    results = [
        'Broken Strings (feat. Nelly Furtado) James Morrison',
        'Broken Strings (feat. James Morrison) Nelly Furtado',
    ],
    match, aux = 0, matches;

Array.prototype.unique = function() {
    var o = {}, i, l = this.length,
        r = [];
    for (i = 0; i < l; i += 1) o[this[i]] = this[i];
    for (i in o) r.push(o[i]);
    return r;
};

String.prototype.ngram = function(n) {
    var i, l = this.length - n,
        r = [];
    for (i = 0; i <= l; i++) {
        r.push(this.substring(i + i + n));
    }
    return r.unique();
};

String.prototype.trigramMatches = function(subject) {
    var appearings = 0,
        trigram = this.ngram(3),
        i,
        l = trigram.length;

    for (i = 0; i < l; i++) {
        if (query.lastIndexOf(trigram[i])) {
            appearings++;
        }
    }

    return appearings;
};

for (var i = 0, l = results.length; i < l; i++) {
    matches = results[i].trigramMatches(query);
    if (matches > aux) {
        match = results[i];
        aux = matches;
    }
}

console.log(match);
console.timeEnd('matching-words');