script.js

/*jslint browser:true */
"use strict";

function addMonths(elem) {
var annualUseKw=0, dailyUseKw=0, i=0, x=0;
var months=document.getElementById(elem).getElementsByTagName('input');
	for(i=0; i<months.length; i++) {
		x=Number(months[i].value);
		annualUseKw += x;
	} // end loop
	dailyUseKw=annualUseKw/365;
	return dailyUseKw;
} // end of function

function sunHours() {
	var hrs;
	var theZone=document.forms.solarForm.zone.selectedIndex;
	theZone +=1; //array offset
	switch(theZone) {
	    case 1:
	        hrs=6;
	        break;
	    case 2:
	        hrs=5.5;
	        break;
	    case 3:
	        hrs=5;
	        break;
	    case 4:
	        hrs=4.5;
	        break;
	    case 5:
	        hrs=4.2;
	        break;
	    case 6:
	        hrs=3.5;
	        break;
	    default:
	         hrs=0;
	} //end switch
	return hrs;
} //  end function

function calculatePanel() {
	var userChoice = document.forms.solarForm.panel.selectedIndex;
	var panelOptions = document.forms.solarForm.panel.options;
	var power = panelOptions[userChoice].value;
	var name = panelOptions[userChoice].text;
	var x=[power, name];
	return x;
} //  end function



function calculateSolar() {
	var dailyUseKw = addMonths('mpc');
	console.log(dailyUseKw);

	var sunHoursPerDay = sunHours();
	console.log(sunHoursPerDay);

	var minKwNeeds = dailyUseKw/sunHoursPerDay;
	console.log(minKwNeeds);

	var realKwNeeds = minKwNeeds*1.25;
	console.log(realKwNeeds);

	var realWattNeeds = realKwNeeds * 1000;
	console.log(realWattNeeds);

	var panelInfo = calculatePanel();
	var panelOutput = panelInfo[0];
	var panelName = panelInfo[1];
	console.log(panelOutput);
	console.log(panelName);

	var panelsNeeded = Math.ceil(realWattNeeds / panelOutput);
	console.log(panelsNeeded);

	var feedback="";
	feedback += "<p>Based on your average daily use of "+Math.round(dailyUseKw)+" Kwh, you will need to purchase  "+panelsNeeded+" "+panelName+" solar panels to offset 100% of your electricity bill.</p>";
	feedback +="<h2>Additional Details</h2>";
	feedback +="<p>Your average daily electricity consumption: "+Math.round(dailyUseKw)+" Kwh per day.</p>";
	feedback +="<p>Average sunshine hours per day: "+sunHoursPerDay+" hours</p>";
	feedback +="<p>Realistic watts needed per hour: "+Math.round(realWattNeeds)+" watts/hour.</p>";
	feedback +="<p>The "+panelName+" panel you selected generates about "+panelOutput+" watts per hour.</p>";

	document.getElementById('feedback').innerHTML=feedback;

} // end of function