13.数组.html 873 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. // typeof [] => object 引用数据类型
  11. // 1.定义数组
  12. var arr = [];
  13. arr[2] = '我的';
  14. arr[0] = '你的';
  15. arr[1] = true;
  16. console.log(arr);
  17. // arr[xx] 下标:下标从0开始
  18. // 2.定义数组
  19. var arr1 = new Array();
  20. arr1 = ['1',2,false,null,undefined];
  21. console.log(arr1,'arr1');
  22. // 3.遍历数组
  23. var arr3 = [12,23,34,45,56,67,78,89,90];
  24. // console.log(arr3.length)
  25. for(var i=0;i<arr3.length;i++){
  26. console.log(i,'i')
  27. document.write("此次循环的值是:" + arr3[i]+"<br>");
  28. }
  29. </script>
  30. </body>
  31. </html>