Troubleshooting JSQR Function Not Defined Error When Generating QR Codes

Learn why you might encounter the "JSQR function not defined" error when attempting to generate QR codes with JavaScript. Find out how to identify and resolve this issue to make your QR code generator function as expected.
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Troubleshooting JSQR Function Not Defined Error When Generating QR Codes

Clicking the "GenQR" button but encountering a "JSQR function is not defined" error can be quite frustrating, especially if you're eager to see your QR code in action. This error typically signals that the JavaScript function meant to handle the generation of QR codes is either missing, not properly included, or incorrectly called in your HTML file.

Understanding the Issue

The “JSQR function not defined” error usually means that the JavaScript environment is unaware of the JSQR function at the time it is invoked. This can be due to multiple reasons:

Script File Not Included: The script containing the JSQR function might not be included before the script that calls it.

Incorrect Function Name: There might be a typo or misspelling in either the function definition or the function call.

Loading Order: The script that defines the JSQR function might be loaded after the script that calls it.

How to Resolve the Error

Check Script Inclusion

Ensure that the script file where the JSQR function is defined is correctly included in your HTML file before any script that calls it:

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Verify the Function Name

Double-check that the function name used in your HTML file matches exactly with the one defined in your JavaScript file:

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Adjust the Loading Order

Make sure that scripts are loaded in the correct order. If you're using an external library or script, it should be loaded before your custom scripts:

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Utilize Async or Defer Attributes

Consider using the async or defer attributes in your script tags to manage asynchronous loading and ensure scripts are executed in the correct order:

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Final Thoughts

The "JSQR function not defined" error can easily be resolved once you ensure that the script where JSQR is defined is properly included and loaded before it is called. Taking the time to verify the script paths, function names, and loading order will help eradicate this error and get your QR code generator working seamlessly.

By following these troubleshooting steps, you can maintain the flow of your application and ensure your QR code generation functionality performs as expected.