很有意思的js考试题目
alert(typeof(NaN)); alert(typeof(Infinity)); alert(typeof(null)); alert(typeof(undefined)); alert(NaN==NaN); alert(NaN!=NaN); alert(NaN>NaN); alert(null==undefined); alert(null>=undefined); alert(null<=undefined); alert(null==null); alert(null!=null); alert(null!=NaN); alert(null==NaN); alert(NaN==undefined); alert(parseInt("123abc")); alert("123abc"-0); alert(Infinity>10); alert(Infinity>"abc"); alert(Infinity==NaN); alert(true==1); alert(new String("abc")=="abc"); alert(new String("abc")==="abc"); function step(a){ return function(x){ return x+a++; } } var a = step(10); var b = step(20); alert(a(10)); alert(b(20)); var a="123abc"; alert(typeof(a++)); alert(a);