Add 2 calculation capabilities to an existing js file

Hi, I currently have an HTML eCommerce website with products allowing for the selection of a color option. I need to have 2 more options, one for size and 1 for style that will display the price being charged. Please take note that the price will be a combination of both the size AND the style such as Style-A + Size-S = 1 price Style B + Size-S = another price --- Style-A + Size-M = another price, etc. The price variables should be available for change in the actal html page The current js file will have to be amended for being able to enter this functionality in the web page. Please see HTM code below: <ul class="items-list"> <li> <div class="input"> <input type="text" name="qty1" maxlength="2"> <input type="hidden" name="product1" value="K.. 400 thread Fitted Twin" data-value="K.. 400 thread Fitted Twin"> <input type="hidden" class="price" name="price1" value="71.00"> </div> <div class="description"> <p><b>100% Organic Cotton Sheet</b> </p> </div> </li> <li> <div class="input"> <select data-option="product1" data-selecttype="Color"> <!--This option is currently enabled and working--> <option>Select a Sheet colour</option> <option>White</option> <option>Ivory</option> <option>Black</option> <!--and more .. --> </select> &ensp; <select data-option="product1" data-selecttype="Style"> <!--<< each combination of style and size will have a different price --> <option>Select a style</option> <option>Fitted Sheet</option> <option>Flat sheet</option> </select> &ensp; <select data-option="product1" data-selecttype="Size"> <!--<< each combination of style and size will have a different price --> <option>Select a size</option> <option>Twin</option> <option>Double</option> <option>Queen</option> <option>King</option> </select>