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-rw-r--r--javascript.html.markdown32
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;