Fix my code

Paste your code and the error message to get the cause, a fixed version and how to avoid it next time.

The prompt is put together in your browser. Nothing you type is uploaded, and favorites and history stay in your browser too.

Good for

A button on your web page does nothing when clicked
A Python script stops halfway with an error message
Code copied from the internet does not work on your machine

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Code required

Error message optional

What it should do optional

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3. Copy the prompt

Where you will paste it

Cloud AILocal small model

ChatGPT, Claude, Gemini, DeepSeek and similar; the full, detailed prompt

Fix my code

## Role
You are a senior engineer and coding coach who finds bugs quickly and explains them so beginners understand.

## Task
My [Please add: Language or tool] code has a problem. Find the cause and fix it.

## Background
- Code: [Please add: Code]

## Requirements
- Say in one sentence where the problem is
- Change only what is needed and mark which lines changed

## Output format
Give, in order: the cause, the full fixed code, what changed, how to avoid it next time. If there is not enough information, tell me what else you need first.

If the information above is not enough to do the task, list the questions you need me to answer first. Do not make anything up.

A filled-in example

Fill it in like this. Press the button below to put the example into the form above.

Language or tool: JavaScript
Code: const total = document.getElementById("total"); button.addEventListener("click", () => { total.textContent = price * qty; });
Error message: Uncaught ReferenceError: button is not defined
What it should do: Clicking the button should show the total price

What the AI's answer looks like

Illustrative excerpt: the real answer depends on the AI you use and what you fill in.

The cause: the code uses button but never looks the button up, so the browser does not know what button is.

Fixed code
```js
const total = document.getElementById("total");
const button = document.getElementById("calc"); // new: find the button first

button.addEventListener("click", () => {
  total.textContent = price * qty;
});
```

What changed: line 2 is new and finds the button by its id (make sure the button's id in your HTML is calc).

Next time: "is not defined" usually means a variable was never declared or its name is misspelled.

Tips

Paste the full error, line numbers included; "it is broken" is hard to diagnose
Remove API keys, passwords and other secrets before pasting code
Ask the AI to explain the fix so you can handle the same error yourself next time

How to use it

Fill in the fields. You can leave a field empty for now; the prompt will show a [Please add] placeholder.
Choose the tone, length and where you will paste it, then press Copy.
Paste it into ChatGPT, Claude, Gemini, DeepSeek or a local model. If the AI asks you questions, answer them and the result gets better.