判断是否在国内

isInChina

function isInChina(cb) {
    return new Promise((resolve, reject) => {
        try {
            let url = "//graph.facebook.com/feed?callback=h"
            let xhr = new XMLHttpRequest()
            let called = false
            xhr.open("GET", url)
            xhr.onreadystatechange = function() {
                if (xhr.readyState === 4 && xhr.status === 200) {
                    called = true
                    resolve(false)
                }
            }
            xhr.send()
            // timeout 1s, this facebook API is very fast.
            setTimeout(function() {
                if (!called) {
                    xhr.abort()
                    resolve(true)
                }
            }, 1000)
        } catch (e) {
            console.error("fqtest", e)
            resolve(true)
        }
    })
}