HTML-类数组属性及其操作

array like attributes and it's operation

1. element.attributes
2. docuement.getElementsByClassName || getElementsByTagName || getElementsByName || querySelectorAll

let el = document.getElementById('app')
let attrs = el.attributes
Array.isArray(attrs)  // => false
// iterate
[...attrs].map(attrs, attr => {
     return {
           name: attr.name,
           value: attr.value
     }
})

// 参见vuejs源码
[].forEach.map(attrs, attr => {
     return {
           name: attr.name,
           value: attr.value
     }
})