JavaScript Where To

The <script> Tag

  • In HTML, JS codes are inserted between <script> and </script> tags.

JS Functions and Events

  • A JavaScript function is a block of code, that can be executed when “called”.

JavaScript in <head> or <body>

  • JS can be placed in the <body>, or in the <head> section of an HTML page, or in both.
  • JavaScript in <head>
  • JavaScript in <body>
  • In this example, a JavaScript function is placed in the <body> section of an HTML page.
  • The function is invoked (called) when a button is clicked.

Note :- Placing scripts at the bottom of the <body> element improves the display speed, because script interpretation slows down the display.

External JavaScript

  • Scripts can also be placed in external files.
  • You can place an external script reference in <head> or <body> as you like.
  • The script will behave as if it was located exactly where the <script> tag is located.
  • External scripts cannot contain <script> tags.

External JavaScript Advantages

  • It separates HTML and Java code.
  • It makes HTML and JavaScript easier to read and maintain.
  • Cached JavaScript files can speed up page loads.