son = new Array();
son[0] = './images/index/15.jpg';
son[1] = './images/index/16.jpg';
son[2] = './images/index/17.jpg';
son[3] = './images/index/18.jpg';
son[4] = './images/index/5.jpg';
son[5] = './images/index/19.jpg';
son[6] = './images/index/4.jpg';
son[7] = './images/index/8.jpg';
son[8] = './images/index/9.jpg';
son[9] = './images/index/10.jpg';
son[10] = './images/index/20.jpg';
son[11] = './images/index/12.jpg';
son[12] = './images/index/13.jpg';
son[13] = './images/index/21.jpg';
var nbre = son.length;
n = Math.floor(Math.random()* +nbre);