function ValidateForm()
{	
	var area = document.getElementById("floor").value;				  
	var conMonth = document.getElementById("constructionmonth").value;
	var conYear = document.getElementById("constructionyear").value;
	var purMonth = document.getElementById("purchasemonth").value;
	var purYear = document.getElementById("purchaseyear").value;
	var units = document.getElementById("units").value;
	var prop = document.getElementById("proptype").value;

	var contPurMonth = document.getElementById("purchasemonth");
	var contPurYear = document.getElementById("purchaseyear");
	var contArea = document.getElementById("floor");
	var contUnits = document.getElementById("units");

	if(isNaN(area) || area == "") 
	{ 
		alert("The floor area supplied is invalid"); 
		return (false); 
	}

	switch(prop)
	{
		case "Metal Clad Warehouse > 3500m2":
			if (area < 3500)
			{
				alert("The floor area must be greater then 3500 m2");
				contArea.value = "3500";
				return (false);	
			}
			break;

		case "Concrete Clad Warehouse > 3500m2":
			if (area < 3500)
			{
				alert("The floor area must be greater then 3500 m2");
				contArea.value = "3500";
				return (false);	
			}
			break;

		default:
			if(area < 35)
			{
				alert("The floor area must be greater then 35 m2");
				contArea.value = "35";
				return (false);
			}
	}		
	

	if(isNaN(units) || units == "") 
	{ 
		alert("The number of units supplied is invalid. Must be a number greater then 1."); 
		return (false); 
	}
	else
	{
		var flag = false;

		switch (prop)
		{
			case "Walk up Unit": 
				if (units < 2 )
					flag = true;
				break;

			case "3-8 Level Unit Development":
				if (units < 2 )
					flag = true;			
				break;
			
			case "> 8 Level Unit Development":
				if (units < 2 )
					flag = true;			
				break;
		}

		if (flag == true)
		{
			alert("The number of units supplied is invalid. Must be 2 or greater.");
			contUnits.value = "2";
			return (false);
		}
	}
	
	if ((Math.min(purYear, conYear) == purYear) && (purYear != conYear))
	{
		alert("The purchase date supplied is invalid. Purchase date must be after the construction date.");
		contPurYear.value = conYear;
		return (false);
	}
	
	if (purYear == conYear)
	{
		if ((Math.min(purMonth, conMonth) == purMonth) && (purMonth != conMonth))
		{
			alert("The purchase date supplied is invalid. Purchase date must be after the construction date.");
			contPurMonth.value = conMonth;
			return (false);
		}
	}

	PerformAction(1);
}

function PerformAction( act_ )
{
	var tc = document.getElementById("tc")
	
	if ( act_ == 1 )
		tc.action = 'result.jsp';
	else
	{
		tc.action = 'depreciation-calculator.jsp';
	}

	tc.submit();
}

function ChangePurDate()
{			  
	var conMonth = document.getElementById("constructionmonth").value;
	var conYear = document.getElementById("constructionyear").value;
	document.getElementById("purchasemonth").value = conMonth;
	document.getElementById("purchaseyear").value = conYear;
}