Testing autofocus

gistfile1.js

function featureTest(element, attribute);
    var el = document.createElement('input');
    if(attribute in el){
       return true;
    else{
       return false;
    }
}

// to test if an browser supports the new HTML 5 autofocus attribute you would do this
if( ! featureText('input', 'autofocus')){
   // place JavaScript fallback (i.e. polyfill here)
}