ModalPopupExtender is a powerful JavaScript library that allows web developers to create dynamic and interactive popups on their websites. One of the key features of this library is the ability to specify JavaScript code to be executed when the popup is shown. In this article, we will explore how to use this feature and its benefits.
First, let's understand what the Shown event of ModalPopupExtender is. When a popup is shown on a webpage, the Shown event is triggered. This event can be used to perform certain actions or tasks that need to be executed when the popup is visible to the user. For example, you may want to display a welcome message or load some data from a server when the popup is shown.
To specify JavaScript for the Shown event, we need to use the OnShown property of ModalPopupExtender. This property takes a JavaScript function as its value. This function will be called when the popup is shown. Let's see an example of how to use this property.
Imagine we have a webpage with a button and a ModalPopupExtender. When the button is clicked, the popup is shown. We want to display a message when the popup is shown. We can achieve this by adding the following code to our webpage:
<button onclick="showPopup()">Show Popup</button>
<ajaxToolkit:ModalPopupExtender ID="modalPopup" runat="server"
TargetControlID="btn" PopupControlID="popup" OnShown="onPopupShown">
</ajaxToolkit:ModalPopupExtender>
<div id="popup">
<h1>Welcome to our website!</h1>
</div>
In the code above, we have added a button and a ModalPopupExtender to our webpage. We have also specified the OnShown property with the value "onPopupShown". Now, let's define the JavaScript function "onPopupShown" in our webpage.
<script type="text/javascript">
function onPopupShown() {
alert("Thank you for visiting our website!");
}
</script>
As you can see, the "onPopupShown" function simply displays an alert message when called. This function will be executed every time the popup is shown on the webpage.
But what if we want to perform some more advanced tasks when the popup is shown? For example, we may want to make an AJAX call to fetch some data from the server and display it in the popup. In such cases, we can use the jQuery library to make the task easier.
Let's see how we can use jQuery to make an AJAX call in the OnShown event. First, we need to include the jQuery library in our webpage. Then, we can modify our "onPopupShown" function as follows:
<script type="text/javascript">
function onPopupShown() {
$.ajax({
url: "data.php",
success: function(data) {
$("#popup").html(data);
}
});
}
</script>
In the code above, we have used the jQuery.ajax() method to make an AJAX call to the "data.php" file. When the call is successful, the "success" function is executed. In this function, we have used the jQuery.html() method to set the content of our popup to the data returned by the server.
As you can see, using JavaScript in the Shown event of ModalPopupExtender allows us to perform various tasks and make our popups more dynamic and interactive. We can also use this feature to add animations or other effects to our popups.
In conclusion, the Shown event of ModalPopupExtender is a powerful feature that allows us to specify JavaScript code to be executed when the popup is shown. By using this feature, we can make our popups more dynamic and interactive, and enhance the user experience on our websites. So, go ahead and try it out in your next project. Happy coding!
