(难度:中等)null转换为数值时是undefined
(难度:中等)null转换为数值时是undefined
相关考题:
( 难度:中等)请选择结果为真的表达式:()A.null instanceof ObjectB.null === undefinedC.null == undefinedD.NaN == NaN
( 难度:中等)以下两个变量a 和b ,a+b 的哪个结果是NaN ?A.var a=undefind; b=NaNB.var a= ‘123’ ; b=NaNC.var a =undefined , b =NaND.var a=NaN , b='undefined'
( 难度:中等)Javascript 中, 以下那两个变量的值不是==:()A.var a=0 , b=-0;B.var a=NaN , b=NaN;C.var a=null ,b=undefined;D.var a=[] , b=false;
( 难度:中等)var arr = new Array(new Array(9,0,3,4,5) , ['a' , 'b' , 'c'] , newArray(2,9,0,6)); 则arr[1][3]= ( )A.cB.6C.4D.undefined
( 难度:中等)有一个变量var a=(100+50)+undefined+NaN,以下哪个是alert(a)的结果?( )A.150undefinedNaNB.NaNC.150undefinedD.10050undefinedNaN
( 难度:中等)[typeof null, null instanceof Object]这些类型的结果是( )A.["object", false]B.[null, false]C.["object", true]D.other
(难度:中等)JavaScript基本数据类型有null、undefined、string、number、boolean