Javascript: alert box, prompt box and confirm box

Alert box:

It displays an alert dialog with a text message and OK button
Example:
Code:
<html>
<head>
<script type=”text/javascript”>
function showAlert()
{
    alert(“Hey!! This is an alert box”);
}
</script>
</head>
<body>
<input type=”button” onClick=”showAlert()” value=”Show” />
</body>
</html>
In above example, only the text Hey!! This is an alert box appears.

Prompt Box:

Prompt is used to allow a user to enter something, and do something with that value.
Code:
<html>
<head>
<script type=”text/javascript”>
function showPrompt()
{
    var name=prompt(“Please enter your name”, “Awaken Nepal”);
    if(name!=null && name!=”")
    {
    document.write(“Hello”+name+”! How are you?”);
    }
}
</script>
</head>
<body>
<input type=”button” onClick=”showPrompt()” value=”Show” />
</body>
</html>
In above example, the alert box with user input field appears to take an input from the user and then do the necessary process.

Confirm Box:

Confirm is used to confirm a user about certain action, and decide between two choices depending on what the user chooses.
Code:
<html>
<head>
<script type=”text/javascript”>
function showConfirm()
{
    if(confirm(“Are you sure you want to delete this record?”))
    {
        alert(“Okay deleted”);
    }
    else
    {
        alert(“Not deleted”);
    }
}
</script>
</head>
<body>
<input type=”button” onClick=”showConfirm()” value=”Show” />
</body>
</html>
In above example, user can choose whether or not an action to be  performed. A confirm box will pop up much like an alert box, but will allow the viewer to press an “OK” or “Cancel” button.