diff options
author | Levi Bostian <levi.bostian@banno.com> | 2013-11-25 09:42:37 -0600 |
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committer | Levi Bostian <levi.bostian@banno.com> | 2013-11-25 09:42:37 -0600 |
commit | af6701904b459b16cf65709cd8c70fd2f5519457 (patch) | |
tree | 68cb4bf9ead32686f492e68528e9f0761e41c500 /javascript.html.markdown | |
parent | df3cc00f5233dac96c0e063d87d3552f493e25f6 (diff) | |
parent | d24c824d388669181eed99c3e94bb25c2914304a (diff) |
Fix conflict bash.
Diffstat (limited to 'javascript.html.markdown')
-rw-r--r-- | javascript.html.markdown | 35 |
1 files changed, 24 insertions, 11 deletions
diff --git a/javascript.html.markdown b/javascript.html.markdown index 1dd6e2be..b6d4c8b7 100644 --- a/javascript.html.markdown +++ b/javascript.html.markdown @@ -1,7 +1,8 @@ --- language: javascript -author: Adam Brenecki -author_url: http://adam.brenecki.id.au +contributors: + - ["Adam Brenecki", "http://adam.brenecki.id.au"] +filename: javascript.js --- Javascript was created by Netscape's Brendan Eich in 1995. It was originally @@ -37,6 +38,8 @@ doStuff() // 1. Numbers, Strings and Operators // Javascript has one number type (which is a 64-bit IEEE 754 double). +// As with Lua, don't freak out about the lack of ints: doubles have a 52-bit +// mantissa, which is enough to store integers up to about 9✕10¹⁵ precisely. 3; // = 3 1.5; // = 1.5 @@ -104,10 +107,10 @@ false; // There's also null and undefined null; // used to indicate a deliberate non-value -undefined; // used to indicate a value is not currently present (although undefined - // is actually a value itself) +undefined; // used to indicate a value is not currently present (although + // undefined is actually a value itself) -// false, null, undefined, NaN, 0 and "" are falsy, and everything else is truthy. +// false, null, undefined, NaN, 0 and "" are falsy; everything else is truthy. // Note that 0 is falsy and "0" is truthy, even though 0 == "0". /////////////////////////////////// @@ -141,6 +144,10 @@ var myArray = ["Hello", 45, true]; // Array indices start at zero. myArray[1]; // = 45 +// Arrays are mutable and of variable length. +myArray.push("World"); +myArray.length; // = 4 + // JavaScript's objects are equivalent to 'dictionaries' or 'maps' in other // languages: an unordered collection of key-value pairs. var myObj = {key1: "Hello", key2: "World"}; @@ -218,6 +225,8 @@ function myFunction(){ // this code will be called in 5 seconds' time } setTimeout(myFunction, 5000); +// Note: setTimeout isn't part of the JS language, but is provided by browsers +// and Node.js. // Function objects don't even have to be declared with a name - you can write // an anonymous function definition directly into the arguments of another. @@ -297,8 +306,8 @@ myObj.myOtherFunc = myOtherFunc; myObj.myOtherFunc(); // = "HELLO WORLD!" // When you call a function with the new keyword, a new object is created, and -// made available to the function via this. Functions designed to be called -// like this are called constructors. +// made available to the function via the this keyword. Functions designed to be +// called like that are called constructors. var MyConstructor = function(){ this.myNumber = 5; @@ -314,7 +323,7 @@ myNewObj.myNumber; // = 5 // property __proto__. While this is useful for explaining prototypes it's not // part of the standard; we'll get to standard ways of using prototypes later. var myObj = { - myString: "Hello world!", + myString: "Hello world!" }; var myPrototype = { meaningOfLife: 42, @@ -322,6 +331,7 @@ var myPrototype = { return this.myString.toLowerCase() } }; + myObj.__proto__ = myPrototype; myObj.meaningOfLife; // = 42 @@ -354,13 +364,16 @@ myObj.meaningOfLife; // = 43 // Constructors have a property called prototype. This is *not* the prototype of // the constructor function itself; instead, it's the prototype that new objects // are given when they're created with that constructor and the new keyword. -myConstructor.prototype = { +MyConstructor.prototype = { + myNumber: 5, getMyNumber: function(){ - return this.myNumber + return this.myNumber; } }; -var myNewObj2 = new myConstructor(); +var myNewObj2 = new MyConstructor(); myNewObj2.getMyNumber(); // = 5 +myNewObj2.myNumber = 6 +myNewObj2.getMyNumber(); // = 6 // Built-in types like strings and numbers also have constructors that create // equivalent wrapper objects. |