You can implement TopUp just by adding a TopUp class to a HTML element. There are multiple TopUp classes of which you can choose from.
For TopUp with default settings, just use 'top_up'. You can also compose the TopUp class which specifies certain TopUp settings.
When composing you can specify:
The composed TopUp class has to begin with 'tu_' followed by the settings joined with underscores.
As an example, use 'tu_ql_iframe' for a TopUp with the 'quicklook' layout and the 'iframe' type.