• Developed at Netscape by Brendan Eich
• Not Java!
• Client-side script
• Interpreted by the browser
• used to access and modify the DOM

• convention for markup object interaction
• language independent
• cross-platform

• Java is an object-oriented programming language
• JavaScript is an object-based scripting language

  <script type="text/javascript" src="my-script.js"></script>

<script type="text/javascript">
   
    // our statements go in here

</script>

• each instruction is a statement
• we use variables to store values

• Number - whole or float
• String - immutable string of characters
• Boolean - true or false
• Undefined - not defined yet
• Null - explicitly empty

var myNumber,
    myString,
    anotherNumber = 12,
    anotherString = 'Hello world!'; 
var myNumber;var myString;var anothernumber = 12;var anotherString = 'Hello world!';
myString = 'Hello everyone!';

• begin: letters, $, _
• contain only: letters, numbers, $, _
• case sensitive
• naming conventions - stick to them!
• (I prefer camel case)
• can store values & expressions
• use typeof to find out the types

/* a multi-line
   comment
   oh yeah */

// a single line comment 
x = 3;y = x * 3; // a single line comment after a statement!

function myFunction() {
  // my statements run here
  console.log('my first function!');
}

myFunction(); 

var myFunction = function(){
    // my statements run here
    console.log('my first function!'); 
};

myFunction();

• arguments
• return values
• function scope
• you can declare functions within functions 
  
  
  whaaaaaat

document.write('this will be written to screen');

alert('this will pop up an alert');

prompt('this will ask the user for a prompt and return the value'); 

var myElement = getElementByID('my-element-id');
myElement.innerHTML = "whatever HTML I want to assign";

* title

* your name

* content: a poem

* external style.css document

* prompt user to enter word for each span tag

* replace HTML within span tag with the user's response