About the scope of Javascript variables and about javascript Variables

About the scope of Javascript variables and about javascript Variables

Scope of variables in Js:

1. There is no block-level scope. The variable scope in Js is not bounded by {}, unlike C/C ++/Java.

For example:

Copy codeThe Code is as follows:
If (true ){
Var name = "qqyumidi ";
}

Alert (name); // result: qqyumidi

Js will add the variables defined in if to the current execution environment, especially when using the for loop, pay attention to the differences with other languages.

Copy codeThe Code is as follows:
For (var I = 0; I <10; I ++ ){
;
}
 
Alert (I); // result: 10

This is just my personal understanding. If you have any mistakes, please let us know.