Table of Contents

JavaScript

Document JavaScript HTML methods.

Overview

In HTML, JavaScript code is inserted between <script> and </script> tags. 

<script>
document.getElementById("demo").innerHTML = "My First JavaScript";
</script>

JavaScript is the default scripting language in HTML if type attribute is not specified. That is, the code below has the same effect as the code above. 

<script type="text/javascript">
document.getElementById("demo").innerHTML = "My First JavaScript";
</script>

Keywords

Keyword Description
var Declares a variable (It should only be used if MUST support old browsers.)
let Declares a block variable
const Declares a block constant
if Marks a block of statements to be executed on a condition
switch Marks a block of statements to be executed in different cases
for Marks a block of statements to be executed in a loop
function Declares a function
return Exits a function
try Implements error handling to a block of statements

HTML Element

Objects

document

Property Description
innerHTML HTML content.
Function Description
getElementById(string) Find an HTML element by id attribute.
write(string) Write content to HTML. This function should only be used for testing

window

Function Description
alert(string) Call up an alert box to display the data.
print() Print the content of the current window.

Debug Method

console.log()

Reference