xml-parse.js

let load = (url) => {
  return new Promise((res, rej) => {
    let request = new XMLHttpRequest()
    request.onreadystatechange = () => {
      if (request.readyState === 4) {
        if (request.status === 200) {
          res(request.responseXML)
        }else{
          rej()
        }
      }
    }
    request.open('GET', url, true)
    request.setRequestHeader('Content-Type', 'text/xml')
    request.send()
  })
}


let textArea = document.querySelector('textarea') // a text area in the html file

load('test.xml')
  .then(doc => {
    console.log('the root is ', doc.documentElement.nodeName)
    console.log('node type ', doc.documentElement.nodeType)
    console.log('node value ', doc.documentElement.nodeValue)
    console.log('node children ', doc.childNodes, doc.childNodes.item(0))
    
  }).catch(err => {
    console.log('error occured')
  })