document.getElementById('txt1').focus();

function calculateVal(obj, multiplyWith, objId)
{
	value = trim(obj.value);
	if(value == '')
	{
		document.getElementById(objId).value = '';
		return;
	}
	if(!isFloat(value))
	{
		document.getElementById(objId).value = '';
		return;
	}
	document.getElementById(objId).value = Round(parseFloat(value) * parseFloat(multiplyWith));
	calculateTotal();
}
function calculateTotal()
{
	var result = 0;
	for(var i=2; i<17; i=i+2)
	{
		if(document.getElementById('txt'+i).value != '')
			result += parseFloat(document.getElementById('txt'+i).value);
	}
	document.getElementById('txt17').value = Round (result);
}
function isFloat(field)
{
	var point=0;
	var i=0;
	var beforePoint=0;
	var afterPoint=0;
	for(var a=0;a<field.length;a++)
	{
    	if(!(field.charAt(a)=="." || field.charAt(a)=="0" || field.charAt(a)=="1" || field.charAt(a)=="2" || field.charAt(a)=="3" || field.charAt(a)=="4" || field.charAt(a)=="5" || field.charAt(a)=="6" || field.charAt(a)=="7" || field.charAt(a)=="8" || field.charAt(a)=="9"))
			return false;
		if(field.charAt(a)==".")
			point++;
	}
	if(point > 1)
		return false;
	if(point == 1)
	{
		while(field.charAt(i)!=".")
		{
			i++;
			beforePoint++;
		}
		afterPoint=field.length-(beforePoint+1);
		if(afterPoint==0 && beforePoint==0)
			return false;
	}
	return true;
}
function Round(number)
{
	number = parseFloat(number);
	var x =  number.toFixed(2);
	return x;
}
function lTrim(String)
{
	var i = 0;
	var j = String.length - 1;

	if (String == null)
		return (false);

	for (i = 0; i < String.length; i++)
	{
		if (String.substr(i, 1) != ' ' &&
		    String.substr(i, 1) != '\t')
			break;
	}

	if (i <= j)
		return (String.substr(i, (j+1)-i));
	else
		return ('');
}

function rTrim(String)
{
	var i = 0;
	var j = String.length - 1;

	if (String == null)
		return (false);

	for(j = String.length - 1; j >= 0; j--)
	{
		if (String.substr(j, 1) != ' ' &&
			String.substr(j, 1) != '\t')
		break;
	}

	if (i <= j)
		return (String.substr(i, (j+1)-i));
	else
		return ('');
}

function trim(String)
{
	if (String == null)
		return (false);

	return rTrim(lTrim(String));
}