var abcd;alert(eval(abcd))的执行结果是( )。
举一反三
- varabcd;alert(eval(abcd))的执行结果是()。
- 分析下面代码输出结果。vara="5",b="4";alert(isNaN(a));//结果是()alert(a+b);//结果是()alert(eval(a+"+"+b));//结果是()
- 已知定义如下var a = "abcd";var b = "abcd";v...nt.writeln(c === d);
- 已知定义如下 var a = "abcd"; var b = "abcd"; var c = new String("abcd"); var d = new String("abcd"); 下列输出是（） document.writeln(a == b); document.writeln(a === b); document.writeln(a == c); document.writeln(a === c); document.writeln(c == d); document.writeln(c === d);
- 已知定义如下 var a = "abcd"; var b = "abcd"; var c = new String("abcd"); var d = new String("abcd"); 下列输出是（） document.writeln(a == b); document.writeln(a === b); document.writeln(a == c); document.writeln(a === c); document.writeln(c == d); document.writeln(c === d);