Concept

The concept of template approach is like any visual tool ( VB, Delphi, .. ). You are dragging control on your form and then in your program you are not worried about visual design of your form, you are worried about data. So in VB you will write TextBox = "Hello" and "Hello" will appear with color, font size ... as you specified in a visual editor. So your visual presentation of data is completely separate from logic of your program.

You will do the same with template package. In your program you will write TextBox = "Hello" and "Hello" will appear in browser. And web designers will worry about how that "Hello" should look in a browser.