lovecoding
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VIP24


			
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  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
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<body>
  <script>
    /* 
      let 和 var的区别
      1.let 不能重复声明
      2.let 没有变量提升
      3.临时失效区  在这区域内  不允许同名的变量出现
      4.let 具有块级作用域
    */
    // var a = 13;

    // let a = 10;
    // let b = 20;
    // a = 30;
    // b = 40;
    // console.log(a,b)

    // var a = 10;
    // var a = 20
    // console.log(a)

    /* let a = 10; */
    /* let a = 20 */
    /* console.log(a) */

    // let a = 10
    // function fn() {
    //   let a = 'abc'
    //   console.log(a)
      
    // }
    // fn()
    // console.log(a)


    var a = true;
    if(a){
      let x = 100
    }
    console.log(x)
  </script>
</body>

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