Displaying a message box in java script
In this demonstration we learn that how to use Java Script to display a message
box to the user. In Java Script there are two types of message box for
displaying information. One is known as “alert” and another one is known as
“confirm”. If you want to display an alert or warning regarding programs then we
use alert () method for displaying message box and if we want to take some
confirmation from user then we use confirm () method for displaying message box.
Displaying message by using alert ()
Code:
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script
type="text/javascript">
function showMessage() {
alert("Wow! You have created first java script
application.");
}
</script>
</head>
<body onload="showMessage()">
</body>
</html>
Here I had created a function named showMessage () which called at the load
event of the body means to say at load event of the html document and display a
message. Remember that for creating a function in java script I used
function as a key word and onload is
named of the event which is automatically called as well as html document is
loaded.
Output of the following code snippet is as follows
Displaying message by using confirm () method
confirm (“<string message>”); method in java script is used to display confirm
message box.
<head>
<title></title>
<script
type="text/javascript">
function showMessage() {
confirm("Wow! You have created first
confirm message box.");
}
</script>
</head>
<body onload="showMessage()">
</body>
</html>
Output of the following code snippet is as follows

Detecting which button is clicked in Confirm dialog box
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script
type="text/javascript">
function showMessage() {
var dd = confirm("Click any button to trace which button is clicked.");
if (dd == true)
{
alert("You had clicked OK button on confirm
dialog box.");
}
else {
alert("You had clicked Cancel button on
confirm dialog box")
}
}
</script>
</head>
<body onload="showMessage()">
</body>
</html>
Output of the following code is as follows

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