JSON.parse(undefined) *should* be an error since it is invalid JSON. The request for docs fix is here:

https://github.com/jquery/api.jquery.com/issues/243

BTW, the jQuery Migrate plugin identifies this. Please use the jQuery Migrate plugin. If you'd like you can submit a pull request to clarify the docs.

I believe this is a poor decision, this is a case where purism creates an unnecessary burden. Plugins and javascript galore have relied on what is a documented behavior and this was not a bad thing. The validation check was in one centralized place. Now every bit of code by everyone else must do the check themselves.

I don't believe that the cost is worth it.

just saying

if (!form.valid()) {

//alert("not valid");

return false;

}

will now fail with "Uncaught SyntaxError: Unexpected token u"

what is the correct way of writing the above then? as far as i

knew that was correct.... now

jquery validate 1.11.0

needs to be updated...or is this part of

jquery.validate.unobtrusive.js

Both of those are plugins, you'd need to ask the plugin author. The jQuery Migrate 1.1.1 plugin should allow the code to work as-is.

Microsoft should not be writing plugins?? Kidding, they need to fix them though

I also disagree with the decision to close this. I don't understand why it can't just do the 1.8.3 behavior.

Anonymous said it best: "I believe this is a poor decision, this is a case where purism creates an unnecessary burden." +1

Please use the jQuery Migrate plugin until any dependent code is fixed, that's why we wrote it. Remediations in your own code should be only a line or two.

+1 for using the old behaviour, this is an unnecessary burden on me as a plugin user - especially since the plugin I have a problem with is not open source (nice one Microsoft). I also don't see why the old behaviour is problematic?

Although I feel similar to most here in that the parseJSON method should probably do some simple checking on the input before attempting to parse the JSON, this is equally an issue caused by Microsoft haphazardly tossing whatever they want into the parser and expecting gold.

I've submitted a bug report to Microsoft for this issue; you can see it at: https://connect.microsoft.com/VisualStudio/feedback/details/786650/jquery-validate-unobtrusive-js-broken-for-jquery-1-9-and-above

Maybe they will get around to fixing it in my lifetime...

Duplicate of #13169.