javascript utility function

util.js

 // Add commas to numbers
function addCommas(n) {
    return String(n).replace(/(\d)(?=(\d{3})+$)/g, '$1,')
}

//check the browser environment
function isWeiXinEnv(){
    var ua = window.navigator.userAgent.toLowerCase();
    return ua.match(/MicroMessenger/i) == 'micromessenger';
}