javascript中var与let的区别
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<script>
// let与var的区别
// 1.只在代码块中有效
for (var i = 0; i < 10; i++) {
}
console.log(i)//打印10
for (let i = 0; i < 10; i++) {
}
console.log(i)//报错
//不能重复声明
var a=1
var a=2
let b=1
let b=2 //报错
//不存在变量提升
console.log(c)
var c="apple"
console.log(d)
let d="banana"
</script>
</body>
</html>