The calculator is built using HTML, CSS, and JavaScript code, with separate files. The JavaScript code includes functions for calculating the sine, cosine, and tangent of an angle, as well as for converting between degrees and radians. The user interface is simple and intuitive, with input fields for the angle and function selection, and a result field for displaying the output.
Overall, it is a well-designed web application that can be a useful tool for anyone who needs to perform basic trigonometric calculations quickly and easily on the web.