How do you set and get ckeditor value by javascript

How do you get data from ckeditor ?
use below code to get data from ckeditor , assume your editor name is 'description'

alert(CKEDITOR.instances.description.getData());

How do you set data in ckeditor ?
use below code to set data in ckeditor , assume your editor name is 'description'

CKEDITOR.instances.description.setData( '<h1>Hello Ubed Khan PHP programmer</h1>' );