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);
答案:
alert(typeof(NaN)); //number alert(typeof(Infinity));//number alert(typeof(null) ); //object alert(typeof(undefined) ); //undefined alert((NaN==NaN) ); // false alert( (NaN!=NaN) ); // true alert((NaN>NaN) ); //false alert((null==undefined) ); //true alert((null>=undefined)); //false alert((null<=undefined) ); //false alert((null==null));//true alert((null!=null) ); //false alert((null!=NaN) ); //true alert((null==NaN) );//fasle alert((NaN==undefined) ); //false alert((parseInt("123abc")));//123 alert(("123abc"-0) ); //NaN alert((Infinity>10)); //true alert((Infinity>"abc")); //false alert((Infinity==NaN));//false alert((true==1) ); //true alert((new String("abc")=="abc")); //true alert((new String("abc")==="abc")); //false function step(a){ return function(x){ return x+a++; } } var a = step(10); var b = step(20); alert(a(10));//20 alert(b(20));// 40 var a="123abc"; alert(typeof(a++));// number alert(a);//NaN
引:http://www.iteye.com/topic/903410