JavaScript Array.indexOf

Posted 2021-05-19

if (typeof Array.indexOf != 'function') {
    Array.prototype.indexOf = function(f, s) {
        if (typeof s == 'undefined') s = 0;
        for (var i = s; i < this.length; i++) {
            if (f === this[i]) return i;
        }
        return -1;
    }
}