function prefecturChange(obj){
	//alert(obj.options[obj.selectedIndex].value);
	
	if("東京23区内" == obj.options[obj.selectedIndex].value){
	  document.getElementById( 'add_borough' ).style.display = 'inline';
	}else{
	  document.getElementById( 'add_borough' ).style.display = 'none';
	}
}
/*
*	window.onload = function() {
*		prefecturChange(document.survey_form.add_prefecture);
*	}
*/