4.运算.html 1.3 KB

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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. // 算数运算 + - * / %(取余/取模)
  11. // console.log(1+1);//2
  12. // console.log(1+'100'); //number + string 拼接
  13. // console.log(1 + true); //2
  14. // console.log(1 + false); //1
  15. // console.log(1 + undefined); //NaN 非法数字
  16. // console.log(1 + null); //1
  17. var a = 20;
  18. console.log("我今年"+a+"岁");
  19. // console.log(1-1);//0
  20. // console.log(1-'100');//-99
  21. // console.log(1 - true); //0
  22. // console.log(1-undefined);//NaN
  23. // console.log(1-null);//1
  24. // console.log(1*2);//2
  25. // console.log(1*'2');//2
  26. // console.log(2*false);//0
  27. // console.log(2*null);//0
  28. // console.log(2*undefined);//NaN
  29. // console.log(10/2);//5
  30. // console.log(10/'2');//5
  31. // console.log(30/false);//Infinity
  32. // console.log(30/null);//Infinity
  33. // console.log(30/undefined);//NaN
  34. console.log(11%3);//2
  35. console.log(11%'3');//2
  36. console.log(11%false);//NaN
  37. console.log(11%null);//NaN
  38. console.log(11%undefined);//NaN
  39. </script>
  40. </body>
  41. </html>