code: function findMetaViewport(head) {
    for (let node = head.firstChild; node !== null; node = node.nextSibling) {
      if (node.tagName === 'meta' && node.attribs.name === 'viewport') {
        return node;
      }
    }
    return null;
  }
docs: Finds and returns the first 'meta charset' element in the head.
  
  @param {Node} head the section to search for the meta charset node.
  @returns {Node} the '<meta charset>' node or null.