Javascript alert dialog box example

 
Javascript alert dialog box is used to display a warning message to the users.
Note: Alert dialog box gives one button “OK”.

Example:

<!DOCTYPE html>
<html>
<body> 
<script>    
function giveWarning() {
   alert("Warning message.");
   document.write ("Warning message.");
} 
</script>   
<p>Click Submit button and see result.</p>      
<form>
 <input type="button" onclick="giveWarning()" value="Submit" />
</form>
</body>
</html>

Try it:

JS Bin on jsbin.com