js function中变量

var globalVar = "I am a global variable";

function exampleFunction() {
    var localVar = "I am a local variable";
    console.log(localVar); // 输出: I am a local variable
    console.log(globalVar); // 输出: I am a global variable
}

exampleFunction();
console.log(localVar); // 报错: localVar is not defined

console.log(x); // 输出: undefined
var x = 10;

console.log(x); // 报错: x is not defined
let x = 10;

function addGlobalVar() {
    globalVar = "New value"; // 没有使用var声明
}

addGlobalVar();
console.log(globalVar); // 输出: New value

function addLocalVar() {
    var localVar = "Local value";
    console.log(localVar);
}

addLocalVar();
console.log(localVar); // 报错: localVar is not defined