// ver 4.1
// for search vehicles (quick + advanced)
// hide fields based on selected fileds
function showHideFields() {
	
  	// for nn4
	if(document.layers)	{		
		if (document.form.vehcategory.value == "All" )
		{
			if (document.form.make.value =="All" )
			{
				if( document.form.model.value == "" || document.form.model.value == " " ) {
					// show all
					document.NUMPLATES.visibility='visible';
					document.VEHICLES.visibility='visible';
				}
				else {
					document.NUMPLATES.visibility='hidden';	// hide number plate				
					document.VEHICLES.visibility='visible';
				}
			}
			else {
				document.NUMPLATES.visibility='hidden';
				document.VEHICLES.visibility='visible';
			}
		}
		else if( document.form.vehcategory.value =="NUMBER_PLATE"  ) {
			document.NUMPLATES.visibility='visible';
			document.VEHICLES.visibility='hidden';
			
		}
		else {
			document.NUMPLATES.visibility='hidden';
			document.VEHICLES.visibility='visible';			
		}
	} // end nn4
	
	//for I.E
	if(document.all){
		if (document.form.vehcategory.value == "All" )
		{
			if (document.form.make.value =="All" )
			{
				if( document.form.model.value == "" ) {
					// show all
					document.all.NUMPLATES.style.visibility='visible';
					document.all.VEHICLES.style.visibility='visible';			
				}
				else {
					document.all.NUMPLATES.style.visibility='hidden';	// hide number plate				
					document.all.VEHICLES.style.visibility='visible';			
				}
			}
			else {
				document.all.NUMPLATES.style.visibility='hidden';
				document.all.VEHICLES.style.visibility='visible';			
			}
		}
		else if( document.form.vehcategory.value =="NUMBER_PLATE"  ) {
			document.all.NUMPLATES.style.visibility='visible';
			document.all.VEHICLES.style.visibility='hidden';
			
		}
		else {
			document.all.NUMPLATES.style.visibility='hidden';
			document.all.VEHICLES.style.visibility='visible';			
		}
		
	} // ie end
	
	// FRO NN6
	if(!document.all && document.getElementById){
		if (document.form.vehcategory.value == "All" )
		{
			if (document.form.make.value =="All" )
			{
				if( document.form.model.value == "" || document.form.model.value == " " ) {
					// show all
					document.getElementById("NUMPLATES").style.visibility='visible';
					document.getElementById("VEHICLES").style.visibility='visible';			
				}
				else {
					document.getElementById("NUMPLATES").style.visibility='hidden';
					document.getElementById("VEHICLES").style.visibility='visible';			
				}
			}
			else {
				document.getElementById("NUMPLATES").style.visibility='hidden';
				document.getElementById("VEHICLES").style.visibility='visible';			
			}
		}
		else if( document.form.vehcategory.value =="NUMBER_PLATE"  ) {
			document.getElementById("NUMPLATES").style.visibility='visible';
			document.getElementById("VEHICLES").style.visibility='hidden';			
		}
		else {
			document.getElementById("NUMPLATES").style.visibility='hidden';
			document.getElementById("VEHICLES").style.visibility='visible';			
		}

	} // end nn6
	
}; // end function