how work html,css and javascript together?

html :

• CONTENT LAYER . html files
• HTML gives the page structure and adds semantics. #html+ css:
• content+ PRESENTATIO .html file+.css file
• css enhance how the HTML content is presented (backgrounds, borders, box dimensions, colors, fonts)

  html+css+ java script:

• BEHAVIOR LAYER
• .html file+.css file+.js file
• adding interactivitely the website

  basic java script:

  var:

• var today= new Date();
• var hourNow = today.getHours();
• var greeting;

  if

  if (hourNow > 18) {

  greeting= ‘Good evening!’; else if (hourNow > 12) { greeting = ‘ Good afternoon!’; else if (hourNow > 0) { greeting = ‘Good morni ng!’; else { greeting = ‘Welcome! ‘ ; }

  LINKING TO A JAVASCRIPT file with html ?

• NUMERIC DATA TYP
• string data type
• boolean data type