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http://learn.appendTo.com : Javascript notes
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//// useful sites | |
// http://jsbin.com | |
// http://jshint.com | |
// http://jslint.com | |
// http://jsfiddle.com | |
// http://stackoverflow.com/questions/11246/best-resources-to-learn-javascript | |
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/A_re-introduction_to_JavaScript?redirectlocale=en-US&redirectslug=JavaScript%2FA_re-introduction_to_JavaScript | |
//// video tutorials | |
// http://learn.appendto.com | |
// Numbers, Strings, and Loose Typing | |
parseInt('3.1416', 10) // 3 | |
parseInt('3.99', 10) // 3 | |
parseInt(3.1416, 10) // 3 | |
parseInt(3.99, 10) // 3 | |
parseInt('oops') // NaN | |
isNaN(parseInt('oops')) // true | |
parseFloat('3.1416') // 3.1416 | |
+ '3.1416' // 3.1416 | |
'foo' + 'bar' // 'foobar' | |
'foo' + '3.1416' // 'foo3.1416' | |
typeof('foo') // 'string' | |
typeof('3.1416') // 'string' | |
typeof(3.1416) // 'number' | |
// Comparisons 1 | |
1 == 1 // true | |
2 == 'something' // false | |
'whiz' < 'bang' // false | |
'foo' >= 'bar' // true | |
1 == '1' // true | |
1 != '1' // false | |
1 === '1' // false | |
1 !== '1' // true | |
0 == false // true | |
0 === false // false | |
9 == 9.0 // true | |
9 === 9.0 // true | |
// If Statement | |
if (condition) statement | |
if (condition) { multiple statements } | |
if (condition) { | |
statement if true | |
} else { | |
statement if false | |
} | |
if (condition) { | |
statment if true | |
} else if { | |
statement if true and previous if is false | |
} | |
// Comparisons 2, Undefined and Null | |
undefined == null // true | |
undefined === null // false | |
// While Loops | |
while (condition) statement // if condition===true then while statement evaluates until the condition===false | |
var x = 0; | |
while (x<5) { | |
console.log(x) | |
x = x + 1 | |
} // 0 1 2 3 4 | |
// For Loops | |
for ([initialExpression]; [condition]; [incrementExpression]) statement | |
var arrrr = [ 'yo', 'ho', 'rum' ] | |
for (index = 0; index < arrrr.length; index++) { | |
console.log(index + ': ' + arrrr[index]); | |
} // 0: yo 1: ho 2: rum | |
for (var index = 0, arrrr = ['yo','ho','rum']; | |
index < arrrr.length; | |
index++) { | |
console.log(index + ': ' + arrrr[index]); | |
} | |
// Objects 1 | |
var alice = { | |
size: 'small', | |
'arch-enemy' : 'the red queen', | |
'age' : 7.5 | |
}; | |
alice.size // 'small' | |
alice.arch-enemy // 'the red queen' | |
alice.age // age | |
// Functions 1 | |
function functionName (parameters) { | |
statement | |
} // define function using function notation | |
var functionName = function(parameters) { | |
statement | |
} // define function using variable notation | |
functionName() // invoke function | |
// Objects 2 | |
var alice = { | |
'age': 7.5, | |
'enemy': { | |
'name': 'Queen of Hearts', | |
'nationality': 'Wonderland' | |
} | |
} | |
alice.age // 7.5 | |
alice.enemy // Object {name: "Queen of Hearts", nationality: "Wonderland"} | |
alice.enemy.name // 'Queen of Hearts' | |
alice.age && alice.enemy // Object {name: "Queen of Hearts", nationality: "Wonderland"} | |
alice.age && alice.enemy && alice.enemy.name // 'Queen of Hearts' | |
alice.enemy.speak = function() { | |
return 'off with your head!!!'; | |
} | |
alice.enemy.speak() // 'off with your head!!!' | |
alice.enemy.speak = function() { | |
return 'I\'m the ' + this.name + ' ... now off with your head!!!'; | |
} | |
alice.enemy.speak() // "I'm the Queen of Hearts ... now off with your head!!!" | |
var alice = { | |
'age': 7.5, | |
'enemy': 'Queen of Hearts' | |
} | |
for (var attr in alice) { | |
console.log(attr + ': ' + alice[attr]) | |
} // age: 7.5 enemy: Queen of Hearts | |
// Array Objects 1 | |
var arrrr = ['bottle','of','rum',5] | |
arrrr.length // 4 | |
arrrr['length'] // 4 | |
typeof(arrrr) // 'object' | |
arrrr[100] = 'test' | |
arrrr.length // 101 | |
arrrr[100] // 'test' | |
var arrrr = ['bottle','of','rum',5] | |
arrrr.push('hello') | |
arrrr.length // 5 | |
arrrr[4] // 'hello' | |
arrrr[arrrr.length-1] // 'hello' | |
var ary = ['foo','bar','baz'] | |
ary.newProp = 'array\'s are objects too!!' | |
for (var i in ary) { | |
console.log(i + ': ' + ary[i]) | |
} // foo bar baz arry's are objects too!! | |
for (var i=0; i<ary.length; i++) { | |
console.log(i + ": " + ary[i]) | |
} // 0: foo 1: bar 2: baz |
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