Скачать или смотреть How to Add JavaScript from Code Behind in C# During Page Load

Discover the simple method to run JavaScript from code-behind C# during page load using `RegisterStartupScript`.
---
This video is based on the question https://stackoverflow.com/q/63525441/ asked by the user 'Nat' ( https://stackoverflow.com/u/9500607/ ) and on the answer https://stackoverflow.com/a/63527969/ provided by the user 'Jeff Mergler' ( https://stackoverflow.com/u/1129926/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to add JavaScript from Code Behind C# ?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Add JavaScript from Code Behind in C# During Page Load

If you're working with ASP.NET Web Forms, you might find yourself needing to execute JavaScript code during a page's load event from the server-side code. This can be quite beneficial for adding functionality or interactivity to your web applications. In this guide, we'll explore how to run JavaScript directly from your C# code-behind, specifically when the page loads.

The Problem

Imagine you have a JavaScript function that you want to execute automatically when a web page is loaded, but you want to control this from your C# code. This is common when you need to manipulate the client-side behavior based on server-side conditions or logic. A typical example could be alerting users not to use certain keys, like showing an alert when they press the Caps Lock key.

Here's the JavaScript you might want to run:

[[See Video to Reveal this Text or Code Snippet]]

The Solution

To successfully add JavaScript from code-behind in C# , you can use the RegisterStartupScript method provided by the ScriptManager class. This method registers a startup script block to be executed when the page is rendered.

Steps to Implement the Solution:

Open Your Code Behind File: This will usually have the .aspx.cs extension.

Use the Page_Load Event: This is where you will add your script registration.

Create Your JavaScript Code as a String: Define the JavaScript you want to execute.

Register the Script: Use ScriptManager.RegisterStartupScript to register your JavaScript.

Here’s how your implementation might look:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code:

Page_Load Method: This is an event handler that gets called every time the page is loaded.

JavaScript String: The JavaScript code is defined as a string in js. This allows you to include it directly in your C# code.

RegisterStartupScript Method:

The first argument is the current page.

The second argument is the type of the current instance.

The third argument is a unique key for the script, which helps avoid duplicate scripts.

The fourth argument is the script string.

The last argument, when set to true, indicates that you want to wrap the script in a <script> tag automatically.

Conclusion

Integrating JavaScript into your ASP.NET Web Forms applications using C# code-behind provides a powerful way to manage client-side behavior dynamically. By leveraging the ScriptManager.RegisterStartupScript method, you can efficiently add JavaScript that executes during the page load event, enhancing interactivity and user experience.

If you have further questions or need additional examples, feel free to ask!