A fast method to select DOM elements

fastSelect.js

function fastSelect(selector) {
  if (selector == "body") {
    return document.body
  }
  else if (selector == "head") {
    return document.head
  }
  else if (/^[\#.]?[\w-]+$/.test(selector)) {
    switch (selector[0]) {
      case "#":
        return document.getElementById(selector.slice(1))
      case ".":
        return document.getElementsByClassName(selector.slice(1))
      default:
        return document.getElementsByTagName(selector)
    }
  }
  return document.querySelectorAll(selector)
}