jQuery

JavaScript libraries
jQuery - popular Javascript library
jQuery docs at jquery.com
jQuery at w3schools
- basic syntax
The "$" syntax:
- Rather than define many new global vars and global functions ("pollute the global namespace") the jQuery library does everything with a single global var jQuery
- "$" is just an alias for the jQuery object
jquery versions
- Link to a specific version rather than "latest version". For example:
- 3.6.0/jquery.js
- 3.6.0/jquery.min.js
- List of deprecated jQuery functions
npm (package manager for JavaScript)
- jQuery
- jQuery plugins

Demos

Anonymous functions

Anonymous functions (un-named functions passed as arguments)
Anonymous functions are part of functional programming.
jQuery and other Javascript libraries promote the use of anonymous functions in Javascript.

Example in jQuery:

 // When button is clicked execute this function: 

 $("#thebutton").click ( function(){		
 	  	 // put lines of code in here 
 	} );

Example in Three.js:

 // After asynchronous Ajax file read finishes, at some time in future, call this function:

 var loader = new THREE.TextureLoader();
 loader.load ( filename, function ( texture ) {			 
		....
	} );

While the functions are parameters to other functions, they can still be either anonymous or non-anonymous.
Sometimes anonymous functions help:
- Just a slightly more complex function definition line, then more or less a normal function.
- Avoid adding yet another function name to the namespace.
Sometimes anonymous functions can get unreadable:
- e.g. When there is another anonymous function defined inside the first one.
Discussion:
- Anonymous functions take a bit of getting used to. Note they are optional.
- If the function is to be reused elsewhere, it should not be anonymous.
- Function names serve the role of forcing the programmer to describe the function in one line.
- Avoiding anonymous JavaScript functions
- Avoiding anonymous functions in jQuery