ClientScript.RegisterStartupScript NOT working on server - asp.net

Question

I'm having troubles with the following piece of code. It works really good in my local machine, but when I deploy it in the dev server it doesn't work at all. I've searched in a lot of places for a solution but with not successfully.
I have a gridview in which one column is a buttonfield. This button field opens a popup displaying the detail of the selected sales order.
In order to show the popup I use the following sentence:
private void OpenPopup(string name_)
{
Page.ClientScript.RegisterStartupScript(typeof(home), "Popup", string.Concat("<script type='text/javascript'>OpenPopup('", name_, "');</script>"));
}
The OpenPopup() is a javascript function which simply displays the popup (I've tested it and it works fine, so I wont show unnecessary code):
When RegisterStartupScript is executed in my local enviroment it works fine and the result in the page source is the following:
<script type='text/javascript'>OpenPopup('items');</script>
Now, when I publish the site and deploy it in the server it doesn't work at all. I've already tried to make it work using Scriptmanager, but with the same result; it works locally but not in the server.
The added script isn't being written at all.
I really apretiate any kind of help. I've already searched a lot with lots of approaches but no solution for me...
Thanks a lot.
/Edit: I do not use updatepanel in the page.

Answer 1

Have you tried using .RegisterClientScriptBlock? This is what I always use in order to call the JS in the codebehind.
Could you try something like the code below?
protected void btnSubmit_Click(object sender, EventArgs e)
{
Boolean dne = false;
StringBuilder errorMessage = new StringBuilder();
String scriptName = "";
if (AdminAccess.DoesUserExist(txtUsername.Text))
{
errorMessage.Append("alert('The selected username " + txtUsername.Text + " is already in use. Please choose another. ');");
scriptName = "duplicateUsername";
if (!ClientScript.IsClientScriptBlockRegistered(scriptName))
{
ScriptManager.RegisterClientScriptBlock(this, this.GetType(), scriptName, errorMessage.ToString(), true);
}
dne = true;
}
}