WebUI: Some changes

I think you can drop "invert".
```
function() {
    if (speed_in_browser_title_bar == "true") {
        /* hide checkbox */
        /* set speed_in_browser_title_bar to "false" */
    } else {
        /* show checkbox */
        /* set speed_in_browser_title_bar to "true" */
    }
}
```