11 .取馀数运算
functionisodd(num ) { return num % 2==1; }functionisEven(num ) { return num % 2==0; }functionisSane(num ) returniseven (num )|isodd ) num; } varvalues=[ 7,4,' 13 ',-9,Infinity]; values.map(isSane ); //[true,true,true,false,false]//%如果不是数值,则' 13 ' %2//1 infinity %2//nan infinity为无限大-9%2///