The page cannot read jQuery

With the continuous development of the Internet, front-end technology is also constantly updated and evolved. Among them, JavaScript is an integral part, and jQuery, as a very popular JavaScript library, has always been a favorite tool for front-end developers. However, in actual development, you will also encounter some problems, one of which is that the page cannot read jQuery.

First of all, it needs to be clear that there are many reasons why the page cannot read jQuery. It may be that the jquery.js file is not loaded correctly or the browser does not have enough support for jQuery. So, how should we solve this problem?

1. Check whether the jQuery file is loaded correctly

First, we need to confirm whether the jquery.js file is loaded correctly into the page. You need to pay attention to the following aspects:

1. Check whether the link path is correct. If the file path is incorrect, the page will not be able to read the jQuery file. You can use your browser's developer tools to check that the link path is correct.

2. Check whether the network connection is normal. If the network is unstable, the jQuery file may not be fully loaded successfully. You can try reloading the page or downloading the jQuery file locally for testing.

3. Check whether the jQuery file exists. If the jquery.js file itself does not exist or the file name is spelled incorrectly, the page will not be able to read jQuery. You need to check that the file exists on the server and that the file name is spelled correctly.

2. Confirm whether the browser supports jQuery

Some older versions of browsers or mobile devices lack support for the new generation of JavaScript. If you're having trouble with a relatively new version of jQuery, first make sure your browser supports jQuery.

You can use the CanIUse website to check whether jQuery-related properties or methods are supported by the browser, and you can also use Modernizr to detect browser compatibility.

3. Avoid jQuery conflicts

In actual development, multiple JavaScript libraries or self-developed plug-ins may be used at the same time. At this time, jQuery conflicts may occur. What are jQuery conflicts? Simply put, multiple versions of jQuery appear on the same page, which will cause the page to be unable to read jQuery correctly.

In order to avoid this conflict, you can use the jQuery.noConflict() method to solve it. This method restores the $ symbol to its original state, thus avoiding conflicts with other JavaScript libraries or plugins.

4. Use CDN

In actual development, you can use CDN to reference jQuery files, which can greatly improve the page loading speed. A CDN is a fast, reliable global server network. When a user visits a website page, the CDN server will automatically select a server with the fastest network to provide services for the user.

The commonly used jQuery CDN mainly includes the following:

1. Google CDN
2. Microsoft CDN
3. jQuery CDN

When referencing jQuery, we can use the following code:

This ensures that the page can read the jQuery file correctly.

Summary

The page cannot read jQuery is a common problem in front-end development, but as long as you understand the possible reasons and take corresponding solutions, you can avoid such situations. You need to ensure that jQuery files are loaded into the page correctly, that the browser supports jQuery, to avoid jQuery conflicts, and to improve page load speeds such as using a CDN.

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