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JavaScript简单计算器

程序员文章站 2022-03-13 13:58:40
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  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4. <meta charset="UTF-8">
  5. <title>简单计算器</title>
  6. </head>
  7. <body>
  8. <div>
  9. <input type="text" id="num1" value="">
  10. <select id="yunsuanfu">
  11. <option value="请选择">请选择</option>
  12. <option value="+">+</option>
  13. <option value="-">-</option>
  14. <option value="*">*</option>
  15. <option value="/">/</option>
  16. <option value="%">%</option>
  17. </select>
  18. <input type="text" id="num2" value="">
  19. <button id="count">
  20. 计算
  21. </button>
  22. <p id="jieguo"></p>
  23. </div>
  24. </body>
  25. <script>
  26. var count = document.getElementById('count');
  27. count.onclick = function(){
  28. var num1 =document.getElementById('num1').value;
  29. var num2 =document.getElementById('num2').value;
  30. var yunsuanfu =document.getElementById('yunsuanfu').value
  31. var re = /^[0-9]+.?[0-9]*/;
  32. if (num1 =='' || num2 ==''){
  33. document.getElementById('jieguo').innerHTML= '错误:计算不能为空'
  34. }
  35. else if(num2 == 0 && (yunsuanfu =='/' || yunsuanfu == '%')){
  36. document.getElementById('jieguo').innerHTML= '错误:被除数不能为0'
  37. }
  38. else if(!re.test(num1) || !re.test(num2)){
  39. document.getElementById('jieguo').innerHTML= '错误:只能填写数字进行计算'
  40. }
  41. else {
  42. num1 = parseFloat(num1);
  43. num2 = parseFloat(num2);
  44. console.log(num1)
  45. console.log(num2)
  46. if(yunsuanfu == '请选择'){
  47. document.getElementById('jieguo').innerHTML='请选择运算符';
  48. }
  49. if(yunsuanfu == '+'){
  50. document.getElementById('jieguo').innerHTML=num1+'+'+num2+'='+(num1+num2);
  51. }
  52. if(yunsuanfu == '-'){
  53. document.getElementById('jieguo').innerHTML=num1+'-'+num2+'='+(num1-num2);
  54. }
  55. if(yunsuanfu == '*'){
  56. document.getElementById('jieguo').innerHTML=num1+'*'+num2+'='+(num1*num2);
  57. }
  58. if(yunsuanfu == '/'){
  59. document.getElementById('jieguo').innerHTML=num1+'除'+num2+'='+(num1/num2);
  60. }
  61. if(yunsuanfu == '%'){
  62. document.getElementById('jieguo').innerHTML=num1+'取余'+num2+'='+(num1%num2);
  63. }
  64. }
  65. }
  66. </script>
  67. </html>