Javascript GPA 计算器，计算按钮不起作用

Question

我是 JavaScript 和 html 新手。我试图使用 Javascript 制作一个 GPA 计算器并将其添加到我的博客中:http://comptechniqz.blogspot.in/2016/04/gpa-both-sems.html使用 html 的布局工作得很好，但单击“计算”按钮时不执行任何操作。你能帮我找出我做错了什么吗？

谢谢

我的代码:

<form name="sem1">
      <table border=5 bgcolor=#BADA55 cellpadding="5" cellspacing="2">
                      <th>Subject</th>
                      <th>Grade</th>
             <tr>
                      <td>
                          <select name="subCRsem1_1" >
                                  <option value="3.5">UMA003</option>
                                  <option value="4.5">UCB008</option>
                                  <option value="4.5">UEC001</option>
                                  <option value="2.5">UES009</option>
                                  <option value="4.0">UTA007</option>
                                  <option value="3.0">UEN002</option>
                                  <option value="4.5">UPH004</option>
                                  <option value="4.5">UEE001</option>
                                  <option value="3.0">UHU004</option>
                                  <option value="4.0">UTA008</option>
                          </select>
                      </td>
                      <td><input type=text size=5 name="gr1" align=top maxlength=5></td>
             </tr>
             <tr>
                      <td>
                          <select name="subCRsem1_2" >
                                  <option value="3.5">UMA003</option>
                                  <option value="4.5">UCB008</option>
                                  <option value="4.5">UEC001</option>
                                  <option value="2.5">UES009</option>
                                  <option value="4.0">UTA007</option>
                                  <option value="3.0">UEN002</option>
                                  <option value="4.5">UPH004</option>
                                  <option value="4.5">UEE001</option>
                                  <option value="3.0">UHU004</option>
                                  <option value="4.0">UTA008</option>
                          </select>
                      </td>
                      <td><input type=text size=5 name="gr2" align=top maxlength=5></td>
             </tr>
             <tr>
                      <td>
                          <select name="subCRsem1_3" >
                                  <option value="3.5">UMA003</option>
                                  <option value="4.5">UCB008</option>
                                  <option value="4.5">UEC001</option>
                                  <option value="2.5">UES009</option>
                                  <option value="4.0">UTA007</option>
                                  <option value="3.0">UEN002</option>
                                  <option value="4.5">UPH004</option>
                                  <option value="4.5">UEE001</option>
                                  <option value="3.0">UHU004</option>
                                  <option value="4.0">UTA008</option>
                          </select>
                      </td>
                      <td><input type=text size=5 name="gr3" align=top maxlength=5></td>
             </tr>
             <tr>
                      <td>
                          <select name="subCRsem1_4" >
                                  <option value="3.5">UMA003</option>
                                  <option value="4.5">UCB008</option>
                                  <option value="4.5">UEC001</option>
                                  <option value="2.5">UES009</option>
                                  <option value="4.0">UTA007</option>
                                  <option value="3.0">UEN002</option>
                                  <option value="4.5">UPH004</option>
                                  <option value="4.5">UEE001</option>
                                  <option value="3.0">UHU004</option>
                                  <option value="4.0">UTA008</option>
                          </select>
                      </td>
                      <td><input type=text size=5 name="gr4" align=top maxlength=5></td>
             </tr>
             <tr>
                      <td>
                          <select name="subCRsem1_5" >
                                  <option value="3.5">UMA003</option>
                                  <option value="4.5">UCB008</option>
                                  <option value="4.5">UEC001</option>
                                  <option value="2.5">UES009</option>
                                  <option value="4.0">UTA007</option>
                                  <option value="3.0">UEN002</option>
                                  <option value="4.5">UPH004</option>
                                  <option value="4.5">UEE001</option>
                                  <option value="3.0">UHU004</option>
                                  <option value="4.0">UTA008</option>
                          </select>
                      </td>
                      <td><input type=text size=5 name="gr5" align=top maxlength=5></td>
             </tr>
             <tr>
                      <td>
                          <select name="subCRsem1_6" >
                                  <option value="3.5">UMA003</option>
                                  <option value="4.5">UCB008</option>
                                  <option value="4.5">UEC001</option>
                                  <option value="2.5">UES009</option>
                                  <option value="4.0">UTA007</option>
                                  <option value="3.0">UEN002</option>
                                  <option value="4.5">UPH004</option>
                                  <option value="4.5">UEE001</option>
                                  <option value="3.0">UHU004</option>
                                  <option value="4.0">UTA008</option>
                          </select>
                      </td>
                      <td><input type=text size=5 name="gr6" align=top maxlength=5></td>
             </tr>
             <tr align=center>
                      <td colspan=3><input type="button" value="Calculate" name="CalcButton" onclick="gpaCalc()"></td>
             </tr>
      </table>
</form>

<br>

</center>

<br>


<script language="JavaScript">

<!-- 
function gpaCalc()
{
  //define valid grades and their values
  var grade = new array(11); 
  var credit = new array(11);
  var gradeReceived = new array(6);
  var creditHour = new array(6);

  // define valid grades and their values
  grade = ['A+', 'A', 'A-', 'B', 'B-', 'C', 'C-', 'E', 'F', 'I', 'X'];
  credit = [10, 10, 9, 8, 7, 6, 5, 2, 0, 0, 0];


  // retrieve user input
  gradeReceived[0] = document.sem1.gr1.value;
  gradeReceived[1] = document.sem1.gr2.value;
  gradeReceived[2] = document.sem1.gr3.value;
  gradeReceived[3] = document.sem1.gr4.value;
  gradeReceived[4] = document.sem1.gr5.value;
  gradeReceived[5] = document.sem1.gr6.value;

  // Allocate credits per subject
  creditHour[0] = document.sem1.subCRsem1_1[document.sem1.subCRsem1_1.selectedIndex].value;
  creditHour[1] = document.sem1.subCRsem1_2[document.sem1.subCRsem1_2.selectedIndex].value;
  creditHour[2] = document.sem1.subCRsem1_3[document.sem1.subCRsem1_3.selectedIndex].value;
  creditHour[3] = document.sem1.subCRsem1_4[document.sem1.subCRsem1_4.selectedIndex].value;
  creditHour[4] = document.sem1.subCRsem1_5[document.sem1.subCRsem1_5.selectedIndex].value;
  creditHour[5] = document.sem1.subCRsem1_6[document.sem1.subCRsem1_6.selectedIndex].value;

  // calculate gpa
  var totalGP = 0, GPA, totalHour=0;
  var i, j, validGrade=0;

  for(i=0; i<6; i++)
  {
           for(j=0; j<11;j++)
           {
                    if(gradeReceived[i]==grade[j])
                    {
                     validGrade=1;
                     break;
                    }
           }
           if(validGrade==1)
           {
                            totalGP+=credit[j]*creditHour[i];
                            totalHour+=creditHour[i];
           }
           else
           {
                      alert("Error-  Please use A+, A, A-, B, B-, C, C-, E, F, I or X in grades " );
                      return 0;
           }

  }
  GPA=totalGP/totalHour;
  alert("gpa =  " + eval(GPA));
  return 0;
}
//-->
</script>

Answer 1

限制你的数组。

function gpaCalc()
{
 //define valid grades and their values
  var grade = new array(11); <-------- array has Caps in the A. should be Array(11) for all;
  var credit = new array(11);
  var gradeReceived = new array(6);
  var creditHour = new array(6);

[更新]

更改 JavaScript 的这一部分

if(validGrade==1)
       {
                        totalGP+=credit[j]*creditHour[i];
                        totalHour+=creditHour[i];
       }

对此:

if(validGrade==1)
       {
                        totalGP+=credit[j]*creditHour[i];
                        totalHour+=parseFloat(creditHour[i]);
       }