Create an HTML document called assignment1.html that implements a calorie intake calculator based on the Harris-Benedict equation used by nutritionists and health professionals to determine the daily energy needs based on age, sex, height, weight and level of physical activity.

Follow these guidelines to implement your assignment:

1. Research the formula on wiki:

https://en.wikipedia.org/wiki/Harris%E2%80%93Benedict_equation

2. Build a form to accept all the required input from the visitors.
3. Create a JavaScript file called assignment1.js and write the code for a function that calculates the calorie intake based on the user input.
4. Invoke the function every time the visitor presses a Calculate button on the form.
5. Display the results (BMR and daily calories intake) on the page.
6. Use HTML5 controls that limit/validate the user input.
7. Use good web design practices to enhance visually your html page.
8. Extend the calculator to accept metric measurements.