I’m having trouble getting my JavaScript code to run properly after switching to UpdatePanel controls. Before using UpdatePanels, I could easily trigger JavaScript from my server-side code like this:
This worked perfectly and the script would execute when the page finished loading. However, after I converted my pages to use UpdatePanel for partial postbacks, the JavaScript code doesn’t seem to execute anymore. The UpdatePanel refreshes fine but my client-side scripts are being ignored. Has anyone else run into this issue? What’s the proper way to register JavaScript when working with UpdatePanel controls?
yep, i faced this same issue! the ClientScript registration wont work because UpdatePanel alters the lifecycle. try using ScriptManager.RegisterStartupScript instead; it’s meant for this situation and will ensure your JS runs after the UpdatePanel refreshes.
The problem is that UpdatePanel does partial postbacks, which skip the full page lifecycle that ClientScript methods need. Use ScriptManager.RegisterStartupScript instead - it’s built for partial updates and makes sure your JavaScript runs correctly. I’ve hit this same issue when upgrading old web forms. Call this method after your controls update but before the UpdatePanel finishes rendering. If your script touches DOM elements inside the UpdatePanel, you’ll probably need to re-register it after each postback since those elements can change.
UpdatePanel uses async postbacks that skip the normal page lifecycle - that’s why ClientScript methods don’t work. ClientScript.RegisterClientScriptBlock targets full page loads, but UpdatePanel only refreshes part of the page. I ran into this same issue when adding AJAX to old web forms. Switch to ScriptManager.RegisterStartupScript instead - it’s built for partial postbacks. The syntax is almost the same, just reference the UpdatePanel or Page as your control parameter. Call it during or after Page_Load in your code-behind and it’ll work with UpdatePanel refreshes.