// JavaScript Document
function roundNumber(num, dec) {
 var result = Math.round( Math.round( num * Math.pow( 10, dec + 1 ) ) / Math.pow( 10, 1 ) ) / Math.pow(10,dec);
 return result;
}

function calculate()
{
 var objInput = document.getElementById("totaltaxable");
 var objContrib1 = document.getElementById("contribution1");
 var objContrib2 = document.getElementById("contribution2");

 if((objInput) && (objContrib1) && (objContrib2))
 {
 if(objInput.value == "")
 {
 alert("Please enter your total taxable income");
 objInput.focus();
 }

 var totalincome = objInput.value * 1;
 var lowerlimit = 31920.00;
 var upperlimit = 61920.00;
 var maxcontrib = 0;
var optperscontrib = 0;
 if (totalincome <= lowerlimit)
 maxcontrib = 1000;
 else
 {
 if (totalincome > upperlimit)
 maxcontrib = 0;
 else
 {
 if (totalincome > lowerlimit)
 maxcontrib = 1000- ((totalincome - lowerlimit) * 0.03333);
 }
 }

 if(maxcontrib > 0)
 {
 optperscontrib = maxcontrib / 1;
 }


 objContrib1.innerHTML = roundNumber(optperscontrib, 2);
 objContrib2.innerHTML = roundNumber(maxcontrib, 2);
 }
}