This article covers Render() as a way of adding functionality to USoft UI controls. This is part of the UI Library.
Once the HTML for a control has been created, you can add functionality to the control, such as adding event handlers and instantiating child controls, etc.
For this purpose, each control exposes a Render() function.
$target refers to a jQuery container that contains the element that is the parent for the control to create. propsChild contains additional property settings that are adduced by the parent control. master refers to the control definition of the master.
The Render() function must return a jQuery object containing the newly created control.