xp-loadcss

动态导入js，支持promise

$3

``js
import loadcss from 'xp-loadcss'

// single file
loadcss('https://cdn.bootcss.com/animate.css/3.5.2/animate.css')
.then(() => {
console.log('load success')
})
.catch(() => {
console.log('load error')
})

// multiple files
loadcss(['https://cdn.bootcss.com/animate.css/3.5.2/animate.css', 'https://cdn.bootcss.com/hover.css/2.1.1/css/hover.css'])
.then(() => {
console.log('load success')
})
.catch(() => {
console.log('load error')
})
``