code: function(x) {
              	var index = null, n = this.elements.length;
              	for (var i = 0; i < n; i++) {
              	    if (index === null && this.elements[i] == x) {
              		index = i + 1;
              	    }
              	}
              	return index;
                  }
docs: Returns the index of the first match found