Thanks for your visiting my profile. I am Zhengguo Piao in China. I have learned Objective-C and JavaScript at university. I have more than 6 years history in mobile and PHP developing. I am professional JavaScript developer. I have good experience in some JavaScript library such as jQuery, AngularJS, BackboneJS, ExtJS… Recently I focused on ReactJS and ThreeJS. I am good at iPhone and android app developing, I have good experience in our company and I will work very hard on upwork for client and me. Good luck.