Sometimes you want to put a default value in your input box. Like in a input box you put default value is email and another input box you put default value as user name. Your goal is, whenever the user click on the first input box, by default which is shown “email” text, it will go away automatically and user can write his own email address there. Main purpose is, user have to delete the “email” text manually and then have to write his email address. By implementing a trick could save the time of that manual text deletion.