Attach a function to the focus event. The focus event occurs when the <input> field gets focus:
The focus event occurs when an element gets focus (when selected by a mouse click or by "tab-navigating" to it).
The focus() method triggers the focus event, or attaches a function to run when a focus event occurs.
Tip: This method is often used together with the blur() method.
Trigger the focus event for selected elements:
Attach a function to the focus event:
|function||Optional. Specifies the function to run when the focus event occurs|