3 Ways to Fix “jquery is not defined”

The "jquery is not defined" error is a common JavaScript ReferenceError that occurs when jQuery functions or methods are used without the library being properly loaded or initialized. This issue can arise due to three main reasons: the jQuery library is not included in the HTML file, the script using jQuery is executed before the library loads, or there is a typo in the jQuery reference, such as using lowercase 'jquery' instead of 'jQuery' or '$'. To resolve this error, ensure the jQuery library is loaded before any dependent scripts, use the correct capitalization, and consider utilizing the defer attribute on script tags to ensure scripts are executed in the correct order. Using a Content Delivery Network (CDN) is a popular and efficient way to include jQuery, and it's important to use a version compatible with your code. Additionally, tools like Rollbar can automate error monitoring and triaging, making it easier to manage and fix JavaScript errors in real-time.