What is the scope of js variable?

This article mainly explains "js variable scope refers to what", interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let Xiaobian take you to learn "what js variable scope refers to"!

Variable scope is mainly divided into global scope, local scope and block-level scope.

The corresponding variables are global variables (declared outside all functions), local variables (declared inside a function body or named parameters of a function), and block-level variables (declared inside a block and valid only inside the block).

Variable scopes declared using var have global scope and function scope, and no block-level scope. Both const and let exist.

examples

var v1="a"; let v2="b"; ; scopeTest(); function scopeTest(){ var v1="aa"; let v2="bb"; if(true){ let v1="aaa"; console.log("output v1="+v1); } console.log("output v1="+v1); console.log("output v2="+v2); } console.log("function in vitro output v1="+v1); console.log("function in vitro output v1="+v2); At this point, I believe that everyone has a deeper understanding of "what the scope of js variables refers to", it may be useful to actually operate it! Here is the website, more related content can enter the relevant channels for inquiry, pay attention to us, continue to learn!