$(elem).attr and elem.getAttribute get diffrent values

[anonymous]

var a = $('<div data-a="abc"></div>')
a.data('a');			//abc
a.attr('data-a');		//abc
a[0].setAttribute('a', 'efg');
a.data('a');			//abc
a[0].getAttribute('a');	//efg
a.attr('data-a');		//efg

in the real word, i use a mvvm framework. The attr changes by the framework. i cant use $(elem).data() method to change the value, but i need to get the value.

[anonymous]

sorry，i get wrong test case.

var a = $('<div data-a="abc"></div>')
a.data('a');			//abc
a.attr('data-a');		//abc
a[0].setAttribute('data-a', 'efg');
a.data('a');			//abc
a[0].getAttribute('a');	//efg
a.attr('data-a');		//efg

$(elem).attr get the right value, $(elem).data get the different value

[dmethvin]

The documentation on .data() says that it gets the data- attributes once on first access.

[anonymous]

Replying to dmethvin:

The documentation on .data() says that it gets the data- attributes once on first access.

thanks