I have to disagree with this line. If I checkout your PR and test on IE7 (Vista, if that makes a difference) then that polyfill fails. If I change this line to read 
```
if ( ie() >= 7 ){ //If IE is greater than 7
```

Then everything works as expected. I like the suggested changes for other @ prepended queries, but this line is breaking the polyfill for me. Can you test again?