scope-chain | 易学教程

Double nesting a function-valued return stops from entering the double nested function

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问题 Trying to understand the scope chain and execution context stack articles from David Shariff's Blog, I've tried to understand closures here function foo() { var a = 'private variable'; return function bar() { alert(a); } } var callAlert = foo(); callAlert(); // private variable I just wanted to test if inner function has the variable object just from its parent or from the whole scope chain, so I added a nested function repeating the example: function foo() { var a = 'private variable';

Scope chain look-up vs prototype look-up - Which is when

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问题 If a variable is not available in a function when it's needed, then it's being looked for in the scope chain (which is a closure), but other times it's being searched for in the prototype chain. I am trying to wrap my head around which is happening when. I was wondering if someone could kindly clear the mist for me, or refer me to some literature discussing this topic specifically. For example, would I be right saying that: - Objects and therefore public variables tied to the context (this

Scope chain look-up vs prototype look-up - Which is when

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If a variable is not available in a function when it's needed, then it's being looked for in the scope chain (which is a closure), but other times it's being searched for in the prototype chain. I am trying to wrap my head around which is happening when. I was wondering if someone could kindly clear the mist for me, or refer me to some literature discussing this topic specifically. For example, would I be right saying that: - Objects and therefore public variables tied to the context (this)are always looked up in the prototype chain? - Private variables are always looked up in the scope chain

My function somehow doesn’t have access to its parent closure & is missing variables. How?

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In my top-level function, I’m importing some dependencies using require.js. And they’re there, no problem. Within this function, I define a callback function and attempt to use some of the variables imported via require.js, that is, variables within the parent closure. And they just aren’t there, as confirmed by a breakpoint and a peek at the Chrome inspector’s Scope Variables panel. I understand that fn.apply and friends only set the context as far as this goes, not that they can destroy a reference to a closure or alter the scope chain. define([ 'backbone', 'backbone.vent', 'app/utils/foo',

My function somehow doesn’t have access to its parent closure & is missing variables. How?

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问题 In my top-level function, I’m importing some dependencies using require.js. And they’re there, no problem. Within this function, I define a callback function and attempt to use some of the variables imported via require.js, that is, variables within the parent closure. And they just aren’t there, as confirmed by a breakpoint and a peek at the Chrome inspector’s Scope Variables panel. I understand that fn.apply and friends only set the context as far as this goes, not that they can destroy a

Scope Chain in Javascript

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问题 I\'ve reading scope chain in Javascript but it didn\'t make any sense to me, could any one tell me what is scope chain and how it works with a graphic or something even an idiot can understand. I googled it but I didn\'t find something comprehensible :( 回答1: To understand the scope chain you must know how closures work. A closure is formed when you nest functions, inner functions can refer to the variables present in their outer enclosing functions even after their parent functions have