Function contains

external/.scrollLibs.js:584–600

(parent, child)

  }

  function contains(parent, child) {
    if (child.nodeType == 3) {
      // Android browser always returns false when child is a textnode
      child = child.parentNode
    }
    if (parent.contains) {
      return parent.contains(child)
    }
    do {
      if (child.nodeType == 11) {
        child = child.host
      }
      if (child == parent) {
        return true
      }
    } while ((child = child.parentNode))
  }

  function activeElt() {
    // IE and Edge may throw an "Unspecified Error" when accessing document.activeElement.