加载jQuery与自定义JS文件时出现语法错误的技术求助

Hey there! Let's work through this problem together—since you're new to JS and jQuery, it's totally normal to hit these little roadblocks. Let's break down what's going on:

First, Let's Address the Syntax Error #

The Firefox console is throwing SyntaxError: expected expression, got '}' at test.js line 4, which means your browser is seeing invalid code in that file before it even gets to worrying about loading order. Here are the most common fixes:

• Double-check your test.js code for typos
  Make sure the file exactly matches the code you wrote when it worked inline:

  $(document).ready(function(){
    $("button").click(function(){
      $("p").fadeOut("slow");
    });
  });
  

  Sometimes when copying/pasting or editing, you might accidentally add an extra } or miss a closing bracket. Line 4 in your error is where the parser is choking—verify that line has the correct closing } for the click handler, not an extra one.

• Check for file encoding issues
  If your test.js was saved with a weird encoding (like UTF-8 with BOM), invisible characters at the start of the file can throw off the JS parser. Open the file in a code editor like VS Code, go to the bottom-right corner where it shows the encoding, click it, select "Save with Encoding", and pick "UTF-8" (without BOM).

• Test the code directly in your browser console
  Copy the exact code from test.js, paste it into Firefox's DevTools Console, and hit enter. If it runs without errors, the problem is with the file itself (not the code)—go back to checking encoding or accidental extra characters.

Then, Confirm the Loading Order #

While your current error is syntax-related, it's still critical to make sure your scripts load in the right order:

• standaard.js (which includes jQuery 3.2.1) must load before test.js
• If you load test.js first, jQuery won't be defined yet, and you'd get a different error ($ is not defined).

Here's how your PHP-generated HTML should order the scripts:

<?php
// Your PHP logic here
?>
<!DOCTYPE html>
<html>
<body>
  <button id="button">CLICK HERE!</button>
  <p>Sample text to fade out</p>

  <!-- Load jQuery-containing script first -->
  <script src="standaard.js"></script>
  <!-- Then load your custom script -->
  <script src="test.js"></script>
</body>
</html>

Quick Test to Rule Out Edge Cases #

If the syntax checks out and loading order is correct, try targeting the button by its ID instead of just the button tag—sometimes unexpected elements on the page can interfere, though that's less likely here:

$(document).ready(function(){
  $("#button").click(function(){
    $("p").fadeOut("slow");
  });
});

Give these steps a shot, and I bet you'll get it working in no time!

内容的提问来源于stack exchange，提问作者Danny