vue操作dom

export function addClass(el, className) {
  if (hasClass(el, className)) return
  let newClassName = el.className.split(' ')
  newClassName.push(className)
  el.className = newClassName.join(' ')
}

export function removeClass(el, className) {
  if (!hasClass(el, className)) return
  let newClassName = el.className.split(' ')
  let index = newClassName.findIndex(item => {
    return item == className
  })
  newClassName.splice(index, 1)
  el.className = newClassName.join(' ')
}

export function hasClass(el, className) {
  let reg = new RegExp('(^|\\s)' + className + '($|\\s)')
  return reg.test(el.className)
}

export function getData(el, name, val) {
  const prefix = 'data-'
  name = prefix + name
  if (val) {
    return el.setAttribute(name, val)
  } else {
    return el.getAttribute(name)
  }
}

let elementStyle = document.createElement('div').style

let vendor = (() => {
  let transformNames = {
    webkit: 'webkitTransform',
    Moz: 'MozTransform',
    O: 'OTransform',
    ms: 'msTransform',
    standard: 'transform'
  }
  for (let key in transformNames) {
    if (elementStyle[transformNames[key]] !== undefined) {
      return key
    }
  }
  return false
})()

export function prefixStyle(style) {
  if (vendor === false) {
    return false
  }
  if (vendor === 'standard') {
    return style
  }
  return vendor + style.charAt(0).toUpperCase() + style.substr(1)
}

/*获取网页元素的绝对位置*/
export function getElementLeft(element) {
  var actualLeft = element.offsetLeft;
  var current = element.offsetParent;
  while (current !== null) {
    actualLeft += current.offsetLeft;
    current = current.offsetParent;
  }
  return actualLeft;
}

export function getElementTop(element) {
  var actualTop = element.offsetTop;
  var current = element.offsetParent;
  while (current !== null) {
    actualTop += current.offsetTop;
    current = current.offsetParent;
  }
  return actualTop;
}

export function extend(to, from) {
  for (let key in from) {
    to[key] = from[key];
  }
}

//改变标题
export function changeTitle(title) {
  document.title = title;
  var i = document.createElement('iframe');
  i.src = '//m.baidu.com/favicon.ico';
  i.style.display = 'none';
  i.onload = function () {
    setTimeout(function () {
      i.remove();
    }, 9);
  }
  document.body.appendChild(i);
}