• Follow this tutorial from mmtuts and refactor your finished code into the files of this repository. Be sure to organize your development process using Git Branches
• To learn more about how to organize your code & how to write development-strategies for this project, you can study the using-user-input exercises
• And of course, don't be limited by the tutorial! It's just a starting point. After making the base project work, follow your imagination

Calculator

A simple program that allows users to add, subtract, divide and multiply two numbers.

DOM

tag name	attributes	role
<section>	id='user-interface'	the section that contains all user interface elements
<form>	id="calculator" class="forma"	the form that allows us to handle user's input
<input>	<input type="text" id="value1" name="value1"	this is text field for the first number
<input>	<input type="text" id="value2" name="value2"	this is text field for the second number
<select>	id="operator	this drop-down menu allows user to select desired math operation
<option>	value="add"	this option describe add action
<option>	value="min"	this option describe subtract action
<option>	value="div"	this option describe divide action
<option>	value="mul"	this option describe multiply action
<button>	type="button" id="calculate" class="button"	this button activate the calculation process and display the result.

Styling

class name	description	role
.forma	sets position & font styling for <form>	make input form more user-friendly
.button	sets button with specific margin around it	make button more visible
.result	sets parameters of output field	make output value more visible

Listeners

type	attached to	callback
'click'	id='calculate'	calculateHandler

Handlers

syntax	parameters	return value	behavior
calculateHandler(event)	Event: a user-triggered event	Boolean: should the browser continue as normal?	reads numbers and operation user filled in and return the correct result: passes input through core logic, renders result for user, logs action for developer, and alerts the browser 'OK'

Logic

syntax	parameters	return value	behavior
doMath(operation, a, b)	operation(String) and a,b(Number)	Number	it takes a and b and executes math operation prescribed by operation