I am trying to use a jQuery plugin in a control. The pages that the control can be on use partial postbacks via an UpdatePanel. I include jQuery and the plugin during the control's PreRender event like this:

```
ScriptManager.RegisterClientScriptInclude(
    this,
    this.GetType(),
    "jquery",
    "/_infrastructure/javascript/jquery.js"));

ScriptManager.RegisterClientScriptInclude(
    this,
    this.GetType(),
    "jquery.customPlugin",
    "/_infrastructure/javascript/jquery.customPlugin.js");

```

The customPlugin jQuery plugin sets up a new function called "executeCustomPlugin". Later in the PreRender event of the control, I use the plugin on an element on the control:

```
ScriptManager.RegisterStartupScript(
    this,
    this.GetType(),
    "customPlugin init script",
    @"$(document).ready(function() {
        $('#elementId').executeCustomPlugin();
    });",
    true);

```

However, when it executes, I get the JavaScript error:

```
$('#elementId').executeCustomPlugin is not a function

```

It would seem as if the jQuery plugin is never executed at all, but I set up window.alerts in the jQuery.customPlugin.js file, and it is indeed being executed.

Is there a way to fix this problem?