diff options
Diffstat (limited to 'javascript.html.markdown')
-rw-r--r-- | javascript.html.markdown | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/javascript.html.markdown b/javascript.html.markdown index 34ba9b47..a119be88 100644 --- a/javascript.html.markdown +++ b/javascript.html.markdown @@ -54,6 +54,11 @@ doStuff() // Including uneven division. 5 / 2; // = 2.5 +// And modulo division. +10 % 2; // = 0 +30 % 4; // = 2 +18.5 % 7; // = 4.5 + // Bitwise operations also work; when you perform a bitwise operation your float // is converted to a signed int *up to* 32 bits. 1 << 2; // = 4 @@ -104,7 +109,7 @@ null == undefined; // = true // ...unless you use === "5" === 5; // = false -null === undefined; // = false +null === undefined; // = false // ...which can result in some weird behaviour... 13 + !0; // 14 @@ -144,6 +149,10 @@ someOtherVar = 10; // Variables declared without being assigned to are set to undefined. var someThirdVar; // = undefined +// if you wan't to declare a couple of variables, then you could use a comma +// separator +var someFourthVar = 2, someFifthVar = 4; + // There's shorthand for performing math operations on variables: someVar += 5; // equivalent to someVar = someVar + 5; someVar is 10 now someVar *= 10; // now someVar is 100 @@ -220,15 +229,15 @@ for (var i = 0; i < 5; i++){ //The For/In statement loops iterates over every property across the entire prototype chain var description = ""; -var person = {fname:"Paul", lname:"Ken", age:18}; +var person = {fname:"Paul", lname:"Ken", age:18}; for (var x in person){ description += person[x] + " "; } -//If only want to consider properties attached to the object itself, +//If only want to consider properties attached to the object itself, //and not its prototypes use hasOwnProperty() check var description = ""; -var person = {fname:"Paul", lname:"Ken", age:18}; +var person = {fname:"Paul", lname:"Ken", age:18}; for (var x in person){ if (person.hasOwnProperty(x)){ description += person[x] + " "; @@ -282,12 +291,9 @@ myFunction("foo"); // = "FOO" // Note that the value to be returned must start on the same line as the // `return` keyword, otherwise you'll always return `undefined` due to // automatic semicolon insertion. Watch out for this when using Allman style. -function myFunction() -{ +function myFunction(){ return // <- semicolon automatically inserted here - { - thisIsAn: 'object literal' - } + {thisIsAn: 'object literal'} } myFunction(); // = undefined @@ -301,6 +307,12 @@ setTimeout(myFunction, 5000); // Note: setTimeout isn't part of the JS language, but is provided by browsers // and Node.js. +// Another function provided by browsers is setInterval +function myFunction(){ + // this code will be called every 5 seconds +} +setInterval(myFunction, 5000); + // 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. setTimeout(function(){ @@ -319,7 +331,7 @@ i; // = 5 - not undefined as you'd expect in a block-scoped language // scope. (function(){ var temporary = 5; - // We can access the global scope by assiging to the "global object", which + // We can access the global scope by assigning to the "global object", which // in a web browser is always `window`. The global object may have a // different name in non-browser environments such as Node.js. window.permanent = 10; |