var styleShow = "";			// style.display value to show a field
	var styleHide = "none";		// style.display value to hide a field

	// *****************************************************************************************
	// * Function:
	// *	SwitchFormDisplay( whichdisp )
	// * Description
	// *	If whichdisp = Location - switches the form to Location-specific controls
	// *	If whichdisp = Frequency - switches the form to Frequency-specific controls
	// *	If whichdisp = CallLetters - switches the form to CallLetters-specific controls
	// *****************************************************************************************

function GetCurrentFormMode (myForm)
{
	var validMode = "Location";

	for (i = 0; i < myForm.SearchBy.length; i++)
	{
		if (myForm.SearchBy[i].checked)
		{
			validMode = myForm.SearchBy[i].value;
			break; 
		}
	}
	return validMode;
}

function InitFormLayout ()
{
	if ((document.forms) && (document.forms['DynForm']))
	{
		var validMode = GetCurrentFormMode (document.forms['DynForm']);
		SwitchFormDisplay (validMode);
	}
}

function SwitchFormDisplay ( whichdisp )
{
	var i = 0;
	
	var LocRows = 2;
	var ShowLoc = styleShow;
	
	var FreqRows = 2;
	var ShowFreq = styleShow;
	
	var CLRows = 2;
	var ShowCL = styleShow;
	
	var ShowState = styleShow;
	
	if (whichdisp == 'Location')
	{
		ShowFreq = styleHide;
		ShowCL = styleHide;
		ShowState = styleShow;
	}
	else if (whichdisp == 'Frequency')
	{
		ShowLoc = styleHide;
		ShowCL = styleHide;
	}
	else if (whichdisp == 'CallLetters')
	{
		ShowLoc = styleHide;
		ShowFreq = styleHide;
		ShowState = styleHide;
	}
	
	var Tempvar;

	for (i = 1; i <= LocRows; i++)
	{
		document.getElementById("LocationSpec" + i).style.display = ShowLoc;
	}
	
	for (i = 1; i <= FreqRows; i++)
	{
		document.getElementById("FrequencySpec" + i).style.display = ShowFreq;
	}
	
	for (i = 1; i <= CLRows; i++)
	{
		document.getElementById("CallLettersSpec" + i).style.display = ShowCL;
	}
	
	for (i = 1; i <= 2; i++)
	{
		document.getElementById("StateSel" + i).style.display = ShowState;
	}
}

function ValidateInput (myForm)
{
	var validMode = GetCurrentFormMode (myForm);

	for (i = 0; i < myForm.SearchBy.length; i++)
	{
		if (myForm.SearchBy[i].checked)
		{
			validMode = myForm.SearchBy[i].value;
			break; 
		}
	}
	
	var RetVal = true;
	
	if (validMode == "Location")
	{
		if ((myForm.city.value == '') && (myForm.product.options[myForm.product.selectedIndex].value == 'ALL'))
		{
			alert ('When searching for all available programs, both City and State are required.');
			RetVal = false;
		}
	}
	else if (validMode == "Frequency")
	{
		if (myForm.frequency.value == '')
		{
			alert ('Frequency is required when searching by Frequency.');
			RetVal = false;
		}
		else if (isNaN(myForm.frequency.value))
		{
			alert ('Frequency must be a number.');
			RetVal = false;
		}
		else
		{
			var TheirFreq = parseFloat(myForm.frequency.value);
			
			if ((TheirFreq < 88) || (TheirFreq > 1700) || ((TheirFreq > 108) && (TheirFreq < 540)))
			{
				alert ('Frequency is out of range.');
				RetVal = false;
			}
		}
	}
	else if (validMode == "CallLetters")
	{
		if (myForm.callletters.value == '')
		{
			alert ('Call Letters are required when searching by Call Letters.');
			RetVal = false;
		}
	}
	
	return RetVal;
}