I've got a checkbox, which should go to a method in the codebehind file.
This is my aspx code:

```
<input name="fullscreen_chbx" type="checkbox" id="fullscreen_chbx"  onclick="fullscreen_chbx_Click" runat="server"/>

```

And this is my codebehind code. The code should work but it doesn't even execute the method.

```
protected void fullscreen_chbx_Click(object sender, EventArgs e)
{
    bool fullscreen = false;

    if (fullscreen == false)
    {
        InputSimulator.SimulateKeyPress(VirtualKeyCode.F11);
    }
    else
    {
        InputSimulator.SimulateKeyPress(VirtualKeyCode.F11);

    } 

```

There's always this error in the aspx file: runtime error in JavaScript: "fullscreen\_chbx\_Click" is undefined.
Why is there a error with javascript?