jquery/jquery — pull request #1644 by yaohiyang (2014-08-20 05:27:29+00:00)
Title: 1.x master

Hi, I recently was learning jquery source code, I think this place needs a little modification.
```javascript
jQuery.fn.extend({
offset: function( options ) {
if ( arguments.length ) {
return options === undefined ?
this :
this.each(function( i ) {
jQuery.offset.setOffset( this, options, i );
});
}
...
```
If the 'options' is a empty object, I think 'offset' should return 'this'.
```javascript
jQuery.fn.extend({
offset: function( options ) {
if ( arguments.length ) {
return options === undefined || jQuery.isEmptyObject( options ) ?
this :
this.each(function( i ) {
jQuery.offset.setOffset( this, options, i );
});
}
...
```
As above, I added a method “ jQuery.isEmptyObject ” to verify the value of "options".