Django/Heroku网站中JavaScript对象数据修改方法咨询

Absolutely, you can modify your data objects directly in JavaScript to store values received from an iframe's postMessage—let's break down how to make this work smoothly with your setup.

Step 1: Safely Listen for postMessage Events #

First, set up a listener to catch messages from your iframe. Always validate the message origin to avoid security risks from untrusted sources:

// Initialize your game object (if not already defined)
let game = {
  high_score: 0 // Default starting value
};

// Listen for incoming messages from the iframe
window.addEventListener('message', (event) => {
  // Replace this with your iframe's actual domain to restrict trusted sources
  const trustedOrigin = 'https://your-iframe-domain.com';
  if (event.origin !== trustedOrigin) return;

  // Assume the iframe sends data structured like { highScore: 1250 }
  const incomingData = event.data;
  
  // Update the game object with the new high score
  if (incomingData.highScore !== undefined) {
    game.high_score = incomingData.highScore;
    // Trigger a DOM update to reflect the new value in your HTML
    refreshScoreDisplay();
  }
});

Step 2: Sync the Updated Object with Your HTML #

The {{ game.high_score }} syntax you're using likely renders the value once when the page loads (static templating). To make the HTML update after modifying the JavaScript object, you'll need to refresh the DOM element displaying the score (or leverage a framework's reactive system if you're using one):

For Vanilla JavaScript (No Framework) #

Create a simple function to update the specific DOM element:

function refreshScoreDisplay() {
  // Target the element where your high score is shown
  const scoreElement = document.getElementById('high-score-display');
  if (scoreElement) {
    scoreElement.textContent = game.high_score;
  }
}

Adjust your HTML to include an element with that ID (keep the template tag for initial rendering, then let JS take over updates):

<!-- Initial render uses your template syntax; JS updates it dynamically afterward -->
<p>High Score: <span id="high-score-display">{{ game.high_score }}</span></p>

If Using a Framework (Vue, React, etc.) #

If you're working with a reactive framework, modifying the game object directly will automatically trigger a view update. For example, in Vue:

// Inside your Vue component
data() {
  return {
    game: {
      high_score: 0
    }
  }
},
methods: {
  handleIframeMessage(event) {
    if (event.origin === 'https://your-iframe-domain.com') {
      this.game.high_score = event.data.highScore;
      // No manual DOM updates needed—Vue handles reactivity automatically
    }
  }
},
mounted() {
  window.addEventListener('message', this.handleIframeMessage);
}

Key Notes #

• Security First: Never skip validating event.origin—this prevents malicious sites from sending fake data to your application.
• Reactivity vs. Static Rendering: The initial {{ game.high_score }} works because it's rendered server-side or on page load. Once the page is live, JavaScript needs to update the DOM directly (or rely on framework reactivity) to show changes to the object.

内容的提问来源于stack exchange，提问作者Grak