Fallback API needs setters as well as getters

[aaronmgriffin]

The defineProp calls for document.hidden and document.visibilityState only contain getters. In older versions of safari this causes the subsequent sets of these properties to error with the message "TypeError: setting a property that has only a getter"

[dcherman]

Do you have a specific version where this breaks for a support comment, and can you make a pull request adding two $.noop settings to each of the descriptors?

[aaronmgriffin]

Using browserstack I was able to get it to happen on Safari 5.1 - I didn't test any other versions.

I didn't use noop in my fix, I added actual setters

diff -r e71402529c71 -r 25f8f99f4a29 assets-src/js/jquery.pagevisibility.js
--- a/assets-src/js/jquery.pagevisibility.js        Mon Apr 06 15:45:06 2015 -0500
+++ b/assets-src/js/jquery.pagevisibility.js        Tue Apr 07 10:50:28 2015 -0500
@@ -40,12 +40,18 @@
             defineProp( document, "hidden", {
                 get: function() {
                     return polyfillHidden;
+                },
+                set: function(value) {
+                    polyfillHidden = value;
                 }
             });

             defineProp( document, "visibilityState", {
                 get: function() {
                     return visibilityState;
+                },
+                set: function(value) {
+                    visibilityState = value;
                 }
             });
         }

I don't have the time to submit a PR at the moment, so I'm hoping posting a diff would suffice. If not, let me know, and I can get to it later in the day

[dcherman]

Would certainly be appreciated, but I can get to it later this week if time is a concern.

The setters should definitely be no-op rather than actual setters in order to match what the actual API is; you can't change document.hidden by setting it to true in browsers that have the actual API, so this setting should not be user modifiable in the ideal case.

[aaronmgriffin]

Ah, I see this in the comment right below.

// In browsers that support Object.defineProperty,
// setting the two properties on document is essentially a no-op.
// In other older browsers, this is how we'll keep the properties in sync,
// although it's more prone to tampering than with Object.defineProperty.

I'll make the change later on an retest to ensure it's still okay with $.noop