Pop Up on Browser

<input class="btn" type="button" onclick="alert('Hey, remember to tell your friends us');" value="Alert Example">

<input class="btn" type="button" onclick="confirm('Are you sure you want to delete the Internet?');" value="Confirm Example">

<input class="btn" type="button" onclick="prompt('Please enter your favorite website', 'Javascript Explorer');" value="Prompt Example">

<input  class="btn"  type="button" onDblClick="alert('Hey, remember what I said!');" value="Double Click" />