code: function copyTextUsingDOM (str) {
    const tempElem = document.createElement('div')
    // Setting an individual property does not support `!important`, so we set the
    // whole style instead of just the `-webkit-user-select` property.
    tempElem.setAttribute('style', '-webkit-user-select: text !important')
  
    // Use shadow DOM if available.
    let spanParent = tempElem
    if (tempElem.attachShadow) {
      spanParent = tempElem.attachShadow({ mode: 'open' })
    }
  
    const span = document.createElement('span')
    span.innerText = str
  
    spanParent.appendChild(span)
    document.body.appendChild(tempElem)
    selectionSet(span)
  
    const result = document.execCommand('copy')
  
    selectionClear()
    document.body.removeChild(tempElem)
  
    return result
  }
docs: for iOS Safari
  @param {String} str
  
  @return {Boolean}