var xmlhttp;

function tax(employstatus, age, gender, earnings)
{
//taking values
var empstatus
xmlhttp=GetXmlHttpObject();
if (xmlhttp==null)
  {
  alert ("Browser does not support HTTP Request");
  return;
  }
var url="process.php";
url=url+"?employstatus="+employstatus;
url=url+"&age="+age;
url=url+"&gender="+gender;
url=url+"&earnings="+earnings;

xmlhttp.onreadystatechange=stateChanged;
xmlhttp.open("POST",url,true);
xmlhttp.send(null);
}

function stateChanged()
{
	if (xmlhttp.readyState==4)
	{
		document.getElementById("dvresult").innerHTML=xmlhttp.responseText;
	}
}

function GetXmlHttpObject()
{
	if (window.XMLHttpRequest)
	  {
	  // code for IE7+, Firefox, Chrome, Opera, Safari
	  return new XMLHttpRequest();
	  }
	if (window.ActiveXObject)
	  {
	  // code for IE6, IE5
	  return new ActiveXObject("Microsoft.XMLHTTP");
	  }
	return null;
}

//function for validate the form
function validate(){
	
	var err ='';	
	document.getElementById("dvresult").innerHTML	= '';//For clear the result
	
	aa = document.getElementById('frmcalculator')
	if(aa.selfemployed.checked == false && aa.employed.checked == false)
		err	= "Please Select Employment Status!"
	else if(aa.male.checked == false && aa.female.checked == false)
		err	= "Please Select Gender!"
	else if(aa.earnings.value == '')
		err	= "Please Enter Earnings"
	else if(IsNumeric(aa.earnings.value)== false)	
		err	= "Earnings must be numeric"
	
	if(err)	
		document.getElementById('dverr').innerHTML = err;
	else{
	
		document.getElementById('dverr').innerHTML = '';
	
		if(aa.employed.checked == true && aa.optedout.checked == false)
			employstatus = 'E'
		else
			employstatus = 'O'
			
		if(aa.selfemployed.checked == true)
			employstatus = 'S'
		
		age = aa.age.value;
		if(aa.male.checked == true)	
			gender = 'M';
		else
			gender = 'F';
		
		earnings = aa.earnings.value;
		
		
		tax(employstatus, age, gender, earnings);
	}
}

//click on employed check box
function funemployed(){
	aa = document.getElementById('frmcalculator')
	aa.selfemployed.checked = false;
	aa.employed.checked = true; 
	document.getElementById('obtions').style.display	= '';
//document.getElementById('dverr').innerHTML = '';
} 
//click on selfemployed check box
function funselfemployed(){
	aa = document.getElementById('frmcalculator');
	aa.selfemployed.checked = true;
	aa.employed.checked = false;
	document.getElementById('obtions').style.display	= 'none';
	//document.getElementById('dverr').innerHTML = '';
} 

//click on male check box
function funmale(){
	aa = document.getElementById('frmcalculator');
	aa.male.checked 	= true;
	aa.female.checked	= false;
	//document.getElementById('dverr').innerHTML = '';
} 
//click on female check box
function funfemale(){
	aa = document.getElementById('frmcalculator');
	aa.male.checked 	= false;
	aa.female.checked	= true;
//	document.getElementById('dverr').innerHTML = '';
} 

function IsNumeric(sText)

{
   var ValidChars = "0123456789.,";
   var IsNumber=true;
   var Char;

 
   for (i = 0; i < sText.length && IsNumber == true; i++) 
      { 
      Char = sText.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }
   return IsNumber;
   
}