Help with Javascript for on the fly calculations on mobile app

[cmd]

I am looking for the code to help me with a calculation in a mobile app I am trying to build. I need script that calculates the following:

Value A = diameter
Value B = length
Value C = total weight

Value A times Value B equals Value C

example:
Value A = 49
Value B = 14
Value C = 686

Can someone please help. This is my first venture ever dealing with code.

Thanks
CMD

[007Julien]

There is no need of mobile to calculate 14 times 50 (which is 700) and to subtract 14 to find 14 times 59 !

[cmd]

I am not sure I am following you. Value A and Value B will change each time depending on what the client selects which in turn will cause Value C to change.

[007Julien]

Then follow this recipe

Ingredients :
3 inputs : 2 type text and 1 button to display the result
1 result container (p or div)
Time : 5 minutes.
Equipment :
1 Text editor
Many browsers with console and development tools to test the script.
Preparation steps
1/- Load your favourite template for a page
2/- Display the ingredients with a little CSS
3/- Display a onclick event on the button to call a function which read the to values and return the result.
4/- Write the script which should not be a problem.Multiplication automatically converts strings (read with document.getElementById) to numbers.
Number of servings : More than for or five thousand men with phone