Flex中的if...else if...else语句

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
			   xmlns:s="library://ns.adobe.com/flex/spark" 
			   xmlns:mx="library://ns.adobe.com/flex/mx"
			   width="100%" height="100%">
	<s:layout>
		<s:BasicLayout/>
	</s:layout>
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
	</fx:Declarations>
	<fx:Script>
		<![CDATA[
			import mx.controls.Alert;
			
			public function checkPassword():void
			{
				if(password.text.length <= 0)
				{
					Alert.show("请输入密码！");
				}
				else if(password.text.length < 6)
				{
					Alert.show("密码太短，请重新输入！");
				}
				else if(password.text.length > 20)
				{
					Alert.show("密码太长，请重新输入！");
				}
				else
				{
					Alert.show("输入正确！");
				}
			}
		]]>
	</fx:Script>
	<mx:VBox width="100%" height="100%">
		<s:Group width="100%" height="100%">
			<s:layout>
				<s:VerticalLayout />
			</s:layout>
			<s:TextInput id="password"/>
			<s:Button label="检查密码" click="checkPassword()"/>
		</s:Group>
	</mx:VBox>
</s:Application>