jQuery Migrate 1.1.0 Released

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Thanks for all your feedback on jQuery 1.9.0! We’re preparing an update to address the issues you’ve found already, but in the meantime here’s a new version of the jQuery Migrate plugin. The plugin can be used with either 1.9 or 2.0 to detect deprecated and removed features, or to restore old features for those sticky situations where you need old code to run with new jQuery. The plugin and the messages it generates are documented in the project README.

Judging by many of the questions and bug reports we’ve gotten, far too many of you are trying to do an upgrade to jQuery 1.9 without also using jQuery Migrate. Stop hitting yourself! We created this plugin to make things easy on you. Just include the plugin after your jQuery file to see if it gives you any warnings. The updated jQuery Migrate plugin is available on jQuery’s CDN, and should be available on the Google and Microsoft CDNs within a few days:

<script src="http://code.jquery.com/jquery-1.9.0.js"></script>
<script src="http://code.jquery.com/jquery-migrate-1.1.0.js"></script>

With this development version, warning messages appear on the browser’s console. They all start with JQMIGRATE so they’re easy to find. Just match up each message with its description in the warning list to determine what it means and how it can be fixed.

In a perfect jQuery world, you’ll be able to update your code and run without the jQuery Migrate plugin. But we’re realists, and know that it may be a while before you and the authors of your plugins can get around to fixing compatibility issues. We’ve got you covered there as well. Just use the minified version and the plugin’s fixes will stay, but the warnings will be silenced so you can deploy to production:

<script src="http://code.jquery.com/jquery-1.9.0.min.js"></script>
<script src="http://code.jquery.com/jquery-migrate-1.1.0.min.js"></script>


Finally, remember that you can include the jQuery Migrate plugin with your existing copy of jQuery all the way back to 1.6.4, to see what issues may arise when you do get around to upgrading.

What’s New?

For a detailed list of the issues that were closed you can see the issue tracker; here are the important highlights:

• Traces by default: In browsers that support console.trace(), a stack trace will appear after each warning message to make it easier to diagnose. If you prefer to do your own debugging and want to reduce the console clutter, set jQuery.migrateTrace = false.
• A “Logging is active” message: This message shows up when the plugin starts to let you know it is running. If you don’t see any other messages on the console when testing your pages, you done did good.
• Invalid JSON: Before jQuery 1.9.0, $.parseJSON() would accept some invalid JSON values such as "" or undefined and return null rather than throwing an error. Migrate 1.1.0 warns about this and restores this old behavior.
• HTML strings with leading whitespace: jQuery 1.9 restricts the strings processed by $() for security reasons. Although we recommend you use $.parseHTML() to process arbitrary HTML like templates, the 1.1.0 version of the Migrate plugin restores the old behavior.
• Inappropriate warnings: The Migrate plugin showed a warning for $("<button>", { type: "button" }), which was not correct since that form is allowed on IE6/7/8. That’s been fixed.
• We’re in the jQuery Plugins site: To set a good example, the jQuery Migrate plugin is on the Plugins site! You can always find it on Github as well.