使用JSON.parse加载数据时出现Unexpected token /错误，求解决

Hey there! Let's work through this JSON parsing error together—even after removing the Dreamweaver-added comment, there are a few common culprits to check:

1. Double-Check for Residual Comments or Hidden Characters #

JSON doesn’t support any kind of comment syntax (// or /* */), so even a single leftover / at the start of your file will trigger that "Unexpected token /" error at position 0.

• Open kanjis_n5.json with a plain-text editor like VS Code, Notepad++, or even Windows Notepad (skip Dreamweaver for now—it might sneak in hidden formatting).
• Confirm the very first character in the file is [ (the start of your array), with no leading /, extra whitespace, or invisible characters.

2. Validate Your JSON Syntax #

Your shared JSON snippet looks correct, but tiny typos in the actual file (like mismatched quotes or missing commas) could cause issues. Copy your full JSON content into an online JSON validation tool to catch any syntax errors.

3. Inspect the Raw AJAX Response #

Let’s see exactly what data your script is receiving to rule out cached content or server-side quirks. Modify your loader.js code to log the raw response before parsing:

var ourRequest = new XMLHttpRequest();
ourRequest.open('GET', 'http://127.0.0.1/japones_flat/kanjis_n5.json');
ourRequest.onload = function() {
  "use strict";
  // Log raw response first to check for unexpected content
  console.log("Raw response:", ourRequest.responseText);
  try {
    var response = JSON.parse(ourRequest.responseText);
    console.log(response[0]);
  } catch (e) {
    console.error("Parsing error details:", e);
  }
};
ourRequest.send();

If you see a / at the start of the logged response, your file still has a hidden comment, or the server is returning unexpected content.

4. Bust Browser Cache #

Browsers often cache static files like JSON, so you might still be loading the old version with the comment.

• Force a full refresh with Ctrl + F5 (Windows) or Cmd + Shift + R (Mac).
• Or add a cache-busting parameter to your request URL to guarantee you get the latest file:

  ourRequest.open('GET', 'http://127.0.0.1/japones_flat/kanjis_n5.json?' + new Date().getTime());
  

5. Avoid Editor-Induced BOM Characters #

Some editors (including older Dreamweaver versions) add a UTF-8 BOM (Byte Order Mark)—a hidden character at the start of the file—that breaks JSON parsing. When saving your JSON file in a plain-text editor, select the "UTF-8 (without BOM)" encoding option.

内容的提问来源于stack exchange，提问作者Emanuel Gomez Arn