使用JavaScript向网页中输出<h1>hello</h1>，以下代码中可行的是
<script type="text/javascript">
document.write("<h1>hello</h1>");
</script>
<h1>
<script type="text/javascript">
document.write("hello");
</script>
</h1>
下面不属于空元素的是
A: A .a
B: B. input
C: C.images
D: D.br
答案是A
以下哪四个能使用throw抛出
A: A.Error
B: B.Event
C: C.Objec
D: D.Throwable
E: E.xception
F: F.RuntimeException
正确答案：A,D,E,F
下面代码输出什么
public class Reluctant {
private Reluctant internalInstance = new Reluctant();
public Reluctant() throws Exception {
throw new Exception("I'm not coming out");
}
public static void main(String[] args) {
try {
Reluctant b = new Reluctant();
System.out.println("Surprise!");
} catch (Exception ex) {
System.out.println("I told you so");
}
}
}
A: A. 编译错误
B: B. Surprise!
C: C. 运行时抛错
D: D. I told you so
正确答案：C
使用protocol时，声明一组可选择实现的函数需加上
A: A.@required
B: B.@optional
C: C.@interface
D: D.@protocol
正确答案：B