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JavaScript types preparation for jQuery tutorial and Original From it

2013-06-10 19:17 465 查看
http://learn.jquery.com/javascript-101 This is really helpful for people to learn JavaScript. JS has nothing to do with Java actually !

And some JS data operationing methods are somehow very handy just like other programming languages such as PHP, python and etc.. You could find its awesome functionalities here http://learn.jquery.com/javascript-101/types/ . it's more like PHP while Python also has the method " one_array.pop " or something like that. Need to figure it out from Python Doc.

JS has one_array.pop() one_array.shift() and many other methods to manipulate array object.

Here is a brief difference and usage in jQuery . Easy shot :)

// Checking the type of an arbitrary value.

var myValue = [ 1, 2, 3 ];

// Using JavaScript's typeof operator to test for primitive types:
typeof myValue === "string"; // false
typeof myValue === "number"; // false
typeof myValue === "undefined"; // false
typeof myValue === "boolean"; // false
typeof myValue === "object"; //true       Coz  type "array" is an object in JavaScript :)

// Using strict equality operator to check for null:
myValue === null; // false

// Using jQuery's methods to check for non-primitive types:
jQuery.isFunction( myValue ); // false
jQuery.isPlainObject( myValue ); // false
jQuery.isArray( myValue ); // true. this is better than that you're just informed it's an object only


JS's basic Operators http://learn.jquery.com/javascript-101/operators/

JS's conditional codes : http://learn.jquery.com/javascript-101/conditional-code/

------------These are very useful to do some interesting convenient things.

------------e.g. var foo = bar ? 1 : 0; // if bar is truthy, then foo=1, or foo is assigned with 0

------------In python we have things like this. Figure it out yourself!

Objective_JS:

http://learn.jquery.com/javascript-101/this-keyword/

very interesting keyword : this :)

Paragragh which begins with the blow is very intelligent somehow :

Closures can also be used to resolve issues with the
this
keyword, which is unique to each scope:

------From http://learn.jquery.com/javascript-101/closures/

// Using a closure to access inner and outer object instances simultaneously.
var outerObj = {
myName: "outer",
outerFunction: function() {
// provide a reference to outerObj through innerFunction"s closure
var self = this;
var innerObj = {
myName: "inner",
innerFunction: function() {
console.log( self.myName, this.myName ); // "outer inner"
}
};

innerObj.innerFunction();

console.log( this.myName ); // "outer"
}
};

outerObj.outerFunction();

// Try those codes out in your JavaScript console ( firefox preferred )
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