var str= "
http://ddp-imgs.oss-cn-hangzhou.aliyuncs.com/crm/partner32948318.loginBack_small.jpg";
var name = aaa.substr(str.lastIndexOf('.', str.lastIndexOf('.') - 1) + 1);
console.log(name );
var name = aaa.substr(str.lastIndexOf('.', str.lastIndexOf('.') - 1) + 1);
console.log(name );