Advanced JavaScript（英文版课件）.pptVIP

About the presenter Yahoo! performance  team member YSlow 2.0 architect, dev Book author, open-source  contributor Blog: Before we start… Firebug console Firebug console is a learning tool Firebug console… Inspect the contents of objects by clicking on them Tab auto-complete, a.k.a cheatsheet Arrows ↑ and↓ Fiddle with any page Any page… Fiddle… Objects JavaScript data types primitive and objects number string boolean undefined null What’s an object? a hash of key = value pairs if a key (property) happens to be a function, we can call it a method What’s an object? var obj = { shiny: true, isShiny: function() { return this.shiny; } }; obj.isShiny(); // true Object literal notation { Wrapped in curly braces } ,-delimited properties key:value pairs var obj = {a: 1, b c d: 2}; Arrays Arrays arrays are also objects auto-incremented properties Arrays var a = [1,3,2]; a[0] 1 typeof a object Arrays array objects also get some cool properties... a.length 3 ...and methods a.sort() a.join( ) 1 2 3 Array literal notation var array = [ Square, brackets, wrap, the, comma-delimited, elements ]; JSON JavaScript Object Notation Uses object and array literals Quotes required for properties {num: 1, str: abc, arr: [1,2,3]} Functions Functions functions are objects they have properties they have methods can de copied, deleted, augmented... special feature: invokable Functions function boo(what) { return what; } or var boo = function(what) { return what; }; Functions function boo(what) { return what; } or var boo = function bootoo(what) { return what; }; Functions are objects boo.length 1 bootoo Functions are objects var foo = boo; foo(doodles) doodles foo.call(null, moo!); moo! Return value all functions return a value if they dont explicitly, they return undefined implicitly functions can return other functions Constructors Constructors