一個(gè)經(jīng)典的浮點(diǎn)數(shù)運(yùn)算0.1+0.2 ==?0.30000000000000004
js在運(yùn)算的時(shí)候會(huì)把10進(jìn)制轉(zhuǎn)化為2進(jìn)制;
0.1 =?0.0001100110011001...(無(wú)限)
0.2 = 0.0011001100110011...(無(wú)限)
相加后的二進(jìn)制0.0100110011001100110011001100110011001100110011001100 就等于上面的數(shù)了