Let's break down the issues in your code and walk through a complete, working solution to update quiz scores for specific responses:

Key Issues in Your Original Code #

• Inconsistent Form References: You opened the form with FormApp.openById() but then used getActiveForm() for subsequent calls. This can cause errors if the active form in your session isn't the one you're targeting—stick to the form variable you initialized.
• Incomplete Logic: Your code cuts off before retrieving item responses or implementing the score-setting logic, which is why you're seeing errors when trying to update grades.
• Missing Grade Submission: Even if you set a score, you need to explicitly submit the grade updates to save changes to the form.

Working Solution Code #

Here's a revised script that targets a specific multiple-choice question, maps responses to scores, and updates each response's grade correctly:

function updateQuizResponseScores() {
  // Replace with your actual Form ID
  const targetFormId = 'formID123456';
  const form = FormApp.openById(targetFormId);

  // Define your score mapping: option text → points
  const responseToScore = {
    "1": 10,
    "2": 20,
    "3": 30,
    "4": 40
  };

  // Get all responses from the form
  const allResponses = form.getResponses();

  // Loop through each response to update grades
  allResponses.forEach(response => {
    const itemResponses = response.getItemResponses();

    // Find the target question (adjust the condition to match your question)
    itemResponses.forEach(itemResponse => {
      const question = itemResponse.getItem();
      
      // Match by question title OR ID for precision
      const isTargetQuestion = question.getType() === FormApp.ItemType.MULTIPLE_CHOICE && 
                               question.getTitle() === "Your Target Question Title";

      if (isTargetQuestion) {
        const userAnswer = itemResponse.getResponse();
        // Get the corresponding score (default to 0 if no match)
        const assignedScore = responseToScore[userAnswer] || 0;

        // Create a grade update object for this question
        const gradeUpdate = FormApp.createItemGradeUpdate()
          .setItemId(question.getId())
          .setScore(assignedScore);

        // Submit the grade update to save changes
        response.withItemGradeUpdates([gradeUpdate]).submitGrades();
      }
    });
  });
}

Critical Notes for Success #

• Ensure Quiz Mode is Enabled: Your Google Form must be set to Quiz mode (under Settings → Make this a quiz) to allow score modifications.
• Precision in Question Targeting: Using question.getTitle() is straightforward, but for unchanging references, use question.getId() (you can get the ID via form.getItems() if needed).
• Permissions: The account running the script needs edit access to the form.
• Large Response Sets: If you have hundreds of responses, add batch processing or a time check to avoid hitting Google Apps Script's 6-minute execution limit.

内容的提问来源于stack exchange，提问作者Matthew Eng