$(document).ready(function(){
	
	var building 	= $('#building option:selected').val();
	var room_opt 	= $('#room option').length;
	var rmop 		= $('#room option');
	var selected = new Array();

	$('#building').click(function(){
		if(this.multiple == true){        
			//clearing out previous selections
			$('#room option').hide();
			for(var i=0, a=0; i < this.options.length; i++, a++){
          		if(this.options[i].selected == true){
            		selected[a] = this.options[i].value;
            		if(selected[a] == 'select'){
            			$('#room option').show();
            		}
            		else{
            			$('#room option.' + selected[a]).show();
            		}
          		}    	
          	}
        }
	})
});