// BUILD DROP-DOWNS ----------------------------------------------------------

addOnLoad('init_tenants_startDD()');

// Global variable to hold the options in the second drop-down
var tenants_areas = new Array();

function init_tenants_startDD() {
	if( document.getElementById('tenants_area') ) {
		
		// Put all available options into an Array as objects
		var DD_premises = document.getElementById('tenants_premises');
				DD_premisesOptgroups = DD_premises.getElementsByTagName('OPTGROUP');
		var h = 0;
		for( i = 0 ; i < DD_premisesOptgroups.length ; ++i ) {
			DD_premisesOptions = DD_premisesOptgroups[i].getElementsByTagName('OPTION');
			for( j = 0 ; j < DD_premisesOptions.length ; ++j ) {
				tenants_areas[h] = new tenants_areaObject( DD_premisesOptgroups[i].id+'', DD_premisesOptions[j].text+'', DD_premisesOptions[j].value+'' ); ++h;
			}
		}
		
		// Add the onchange-handler to the drop-downs
		document.getElementById('tenants_area').onchange = tenants_activatePremises;
		document.getElementById('tenants_premises').onchange = DD_goUrl;		
	}
}

function tenants_areaObject(optgroup, text, value) {
	this.optgroup = optgroup;
	this.text = text;
	this.value = value;
}

function tenants_activatePremises() {
	var DD_premises = document.getElementById('tenants_premises');
	var selectedArea = this.options[this.options.selectedIndex].value;
	tenants_clearPremises();
	
	if( this.options[this.options.selectedIndex].value != '#' ) {

		// Insert new options
		DD_premises.options[0] = new Option('V\xE4lj:', '#'); // First add the header
		j = 1; for( i = 0 ; i < tenants_areas.length ; ++i ) {
			if( tenants_areas[i].optgroup == selectedArea ) {
				DD_premises.options[j] = new Option(tenants_areas[i].text, tenants_areas[i].value); ++j;
			}
		} 
		
		// Activate the drop-down		
		DD_premises.disabled = false;
	} else {
	
		// De-activate the drop-down
		DD_premises.disabled = true;
	}
}

function tenants_clearPremises() {
	var DD_premises = document.getElementById('tenants_premises');

	// Clear current options
	DD_premisesOptions = DD_premises.getElementsByTagName('OPTION');	
	for( i = DD_premisesOptions.length -1 ; i > -1 ; --i ) {
		DD_premisesOptions[i].parentNode.removeChild(DD_premisesOptions[i])
	}

	// Clear current optionGroups		
	DD_premisesOptgroups = DD_premises.getElementsByTagName('OPTGROUP');		
	for( i = DD_premisesOptgroups.length -1 ; i > -1 ; --i ) {
		DD_premisesOptgroups[i].parentNode.removeChild(DD_premisesOptgroups[i]);
	}			
}