JQuery .Post Parameters Null In Safari

God. Bless. America.

I spent half the day trying to debug an issue that was infuriating.  Here is the background.  I have an MVC 4 .net 4.0 web application that uses a bunch of JQuery calls to controllers and stores data locally using the HTML 5 SessionStorage object.  My site works ‘perfectly’ in every browser when debugging locally.  When I published to an IIS 7.5 Windows Server 2008 R2 server, everything still worked wonderfully.  Only… I didn’t test the site again in Safari after I published it to production.  Because why would I use Safari for real browsing ;P  Low and behold, I got a call from one of our clients saying the site didn’t work in Safari.  Grr… And I was so close to actually getting some real work done today.

5 hours later, I’ve worked through my lunch trying to track this down.  Using Safari’s (actually decent) developer tools, I could see that the function I was calling from an ‘OnClick(this)’ command was being called appropriately.  The function pulled my SessionStorage object from storage and stored it as a string in a local variable just fine.  Then my .post(url, parameters, function(data) { }); looked good!  The two parameters I specified had the appropriate data displaying when I hovered over it in the Safari JavaScript debugger.  I would step into the next call and the debugger would skip over the success function.  Sure enough, I checked my logs from the server and I got ‘null reference’ errors from the Controller method that JavaScript function called.

I tried at least 30 different solutions, including stepping back my JQuery version (which actually helped somewhat but introduced another 5 problems I didn’t feel like tackling).  What bothered me the whole time is that I have windows authentication enabled on my IIS server.  No forms authentication enabled.  And in Safari, I never got prompted for a password.  I looked everywhere for a setting in Safari that didn’t auto-submit my network credentials, but couldn’t find one.  And the solution was related to that.

The Solution: On the bottom of a stack-overflow page was a post that nobody cared about from a guy who didn’t have his problem solved by the accepted answer above.  He found the issue to be a bug with Safari and Windows Authentication Providers.  Specifically, the Negotiate provider for Windows Authentication.  He disabled that provider and that fixed his problem.  It fixed mine too :-)  I disabled Negotiate under Windows Authentication Providers in IIS and suddenly I was prompted for a password when I tried to login to my site in Safari.  Sure enough, all of my JQuery calls started working.

Here is a link to the article that saved my day: http://stackoverflow.com/questions/15017412/safari-posting-blank-form-to-my-server/15926177#15926177

I gave that guy a +1 because he deserved it.  Thanks Jeff Johnson!

Here are the step-by-step instructions to fix this issue yourself if you’re experiencing the same symptoms Jeff and I did:

• Open IIS on your webserver hosting the site having the problem.
• Left click on the site in question.
• Double click “Authentication” under the IIS sub-heading.

• Right click “Windows Authentication” and select “Providers”.
• Select “Negotiate” and remove it.

• Recycle your app pool for that site.

Capt. Rochefort (If at first you don’t succeed, use your wordsmithing skills to get a better response from Google)