in static/assets/js/modernizr.js [193:220]
function isEventSupported( eventName, element ) {
element = element || document.createElement(TAGNAMES[eventName] || 'div');
eventName = 'on' + eventName;
// When using `setAttribute`, IE skips "unload", WebKit skips "unload" and "resize", whereas `in` "catches" those
var isSupported = eventName in element;
if ( !isSupported ) {
// If it has no `setAttribute` (i.e. doesn't implement Node interface), try generic element
if ( !element.setAttribute ) {
element = document.createElement('div');
}
if ( element.setAttribute && element.removeAttribute ) {
element.setAttribute(eventName, '');
isSupported = is(element[eventName], 'function');
// If property was created, "remove it" (by setting value to `undefined`)
if ( !is(element[eventName], 'undefined') ) {
element[eventName] = undefined;
}
element.removeAttribute(eventName);
}
}
element = null;
return isSupported;
}