4_块作用域.html 392 B

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  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4. <meta charset="UTF-8">
  5. <meta name="viewport" content="width=device-width, initial-scale=1.0">
  6. <title>Document</title>
  7. </head>
  8. <body>
  9. <script>
  10. // if(true){
  11. // var a = 10;
  12. // }
  13. // console.log(a);
  14. if(true){
  15. let a = 10;
  16. }
  17. console.log(a);
  18. </script>
  19. </body>
  20. </html>