Call JavaScript function when CheckBox is checked or unchecked

Here Mudassar Ahmed Khan has explained with an example, how to call JavaScript function when an HTML CheckBox is checked (selected) or unchecked (unselected). For illustration purposes, when the CheckBox is clicked based on whether it is checked (selected) or unchecked (unselected), a JavaScript function will be called within which the HTML DIV with TextBox will be shown or hidden.