mean by scope of variable

ObjectiveIn the 12th chapter, in the description of variable objects, we already know that the data (variables, function declarations, and function parameters) of an execution context are stored as attributes in the variable object. We also know

in the 12th chapter of the description of variable objects, we already know that the data of an execution context (variables, function declarations, and formal parameters of functions) is stored as attributes in the variable object. We also know

PrefaceIn the description of the variable object in Chapter 12th, we already know that the data of the execution context (variables, function declarations, and function parameters) are stored in the variable object as attributes. At the same time,

Deep understandingJavaScriptSeries ( -): Scope chain(Scope Chain)ObjectiveIn the 12th chapter of the description of variable objects, we already know that the data of an execution context (variables, function declarations, and formal parameters of

All variables have global scope, local variables have local scope (note that the parameters of the function are also local variables)1. In the function body, the local variable takes precedence over the global variable with the same name.My

What is the result of the following program? Copy Code code as follows: var foo = 1; function Bar () { if (!foo) { var foo = 10; } Alert (foo); } Bar (); The result is 10; What about the bottom one? Copy

Variable scope(a) package variables$x = 1Here, $x is a package variable. There are 2 important things to know about package variables:1) If there is no other declaration, the variable is the package variable;2) package variables are always

What is the result of the following program? Varfoo1; functionbar () {if (! Foo) {varfoo10;} alert (foo);} bar (); the result is 10. What about the following? Vara1; functionb () {a10; return; function... SyntaxHighlighte What is the result of the

What is the result of the following program? Var foo = 1;Function bar (){If (! Foo ){Var foo = 10;}Alert (foo );}Bar (); The result is 10;   What about the following? Var a = 1;Function B (){A = 10;Return;Function (){}}B ();Alert (); The result is 1.

Document directory Key points of the syntax analysis tree You should have written a similar code. In fact, what I want to express here is that sometimes a method definition is 108,000 different from that used. When the method is executed, what