Definition: The focus method is used to give the focus (ie make current) the object that it belongs to. Giving a text field the focus will move the cursor to that field. Giving a window the focus will move it in front of all of the others. Actions that do not specify a particular object to apply to use the one that has the focus. This is not a reserved word so you can declare your own variable or function called focus but if you do then you will not be able to use this method to control which object is current.
Examples:
window.focus();
