WD - Javascript

• Javascript was released by a popular browser of the time Netscape communicator
• Uses curly brackets to contain the code belonging to functions or “if… then” statements
• Javascript comes with very few modules
• Function to say Hello World in console log

  
  

  function helloWorld() {

      console.log("Hello World");

  }

  helloWorld();
• JavaScript is executed by the client web browser
• As Javascript is executed on the browser the bandiwdth required and server processing is less
• about:blank is a blank page within your browser
•  Variables declared by var keyword are scoped to the immediate function body (hence the function scope) while let variables are scoped to the immediate enclosing block denoted by { }
• Instead of colon what is used to show the beginning of a function in javascript?

  curly bracket
• After each line of code in javascript, except ones with curly brackets what should be at the end of it?

  Semi colon
• JavaScript functions can be stored in an external file rather than added directly to the HTML
• Why are external javascript files used?

  As they can be used across multiple sites
•  Events occur when the user or browser manipulates the page
• The <button> tag can have an onclick event set
• The HTML below creates a button that calls functionFinish on the webpage using the <button> and </button> tags.

  <button onclick="finishFunction()">Finish</button>
• The button inline tag encloses what?

  The button label
• HTML events for scripts:

  onmouseover The mouse hovers over an HTML element

  onmouseout The mouse moves away from an element

  onclick The primary mouse click is done on an elements

  onkeydown A keyboard key is pressed

  onload The browser has finished loading the page
• TO reference in an element in javascript it is best to first assign it to a variable
• Query selector is used as opposed to getElementBy___, it acts similarly returning the first matching element in a document
• jquery can be imported and is used to increase website interactivity, its slogan is 'write less, do more'
• querySelector null is returned if there are no matches.
• what is the syntax of query selector, using 'selector' to represent selectors?


  querySelector(selector)
• A selector references an element inside of a document, they are usually formatted like css rulesets.
• Selectors use entity numbers and class names, like CSS