JS: How to Write a JQuery Plugin

By Xah Lee. Date: . Last updated: .

what's jQuery's $.fn?

It is just a alias to the prototype property. You can see it in the jQuery source code:

jQuery.fn = jQuery.prototype = {
    // …
}

But why we need a alias? Presumably, they aliased so it's shorter to type.

But why is it named “fn”? Perhaps it's because “fn” mean function, and it gives people the right idea of assigning function to it.

[see JS: Prototype and Inheritance]

[see JS: Add Method to Prototype]

How to write a jQuery extension/plugin?

All you have to do is:

$.fn.myNiceExtensionF = function(){…}

Your function shoud return a jQuery object (this) when appropriate, so it's chainable.

Actually, you should do this so your extension can have lots properties/methods:

$.fn.myNiceExtensionF = {
    f1:function(){…},
    f2:function(){…},
    // }

The above is the basic idea, actually more details, see: http://learn.jquery.com/plugins/basic-plugin-creation/

Web Scripting Overview

  1. Browser Window Object, DOM
  2. Intro to Event-Based Programing
  3. JavaScript Load Order

DOM How-To

  1. Basic DOM Methods
  2. Get Element by ID, Tag, Name, Class, CSS
  3. Change CSS
  4. Change Node Content
  5. Create/Insert Node
  6. Remove Node
  7. Get Attribute Value
  8. Set Attribute Value
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  10. List/Add/Remove Class Attribute
  11. Add/Remove Event Handler
  12. Navigate DOM Tree
  13. Node Type, Name, Value

HTML Input

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Web Scripting Examples

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Web Scripting Misc

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  4. Encode URL, Escape String
  5. Browser Info, Navigator Object
  6. Get URL (window.location)
  7. Find Window Width
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  9. WebSocket
  10. Value of “this” in Event Handler
  11. Event Delegation
  12. Get Current Script Tag
  13. insertAfter Element
  14. Randomize List
  15. create Document Fragment
  16. innerHTML, nodeValue, textContent, innerText?
  17. What is Live Object
  18. NodeList vs HTMLCollection
  19. Whitespace Nodes

jQuery

  1. jQuery Basics
  2. jQuery() vs querySelectorAll()
  3. Write JQuery Plugin

node.js

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