Add script12.js
Modify myfirstpage.html header
Add to show DOM oject property
Add to show firstChild and lastChild
Add to show nextSibling and previousSibling
Add function isTextNode
Add function asHTML
Show how to create header and title
Add element img
Add function setNodeAttribute
Add function dom
Modify myfirstpage.html body
Use insertBefore method to place node in front of another child node
Use replaceChild method to replace another node
Use removeChild method to remove child node
Add function removeElement to remove node
Add function makeTable
Add style myfirstpage.html
Add attribute class in p tag